Potential of fruit wastes as natural resources of bioactive compounds

Untargeted metabolomics, optimization of microwave-assisted extraction using Box-Behnken design and evaluation of antioxidant, and antidiabetic activities of sugarcane bagasse

INTRODUCTION

The fruit wastes, in particular agricultural wastes, are considered potential and inexpensive sources of bioactive compounds.

OBJECTIVE

The current study was aimed at the preparation of an optimized extract of sugarcane bagasse using microwave-assisted extraction (MAE) technology and comparative evaluation of chemical composition, antioxidant, and antidiabetic activities with extract prepared through maceration technique.

METHODOLOGY

Box-Behnken Design (BDD) with response surface methodology was applied to observe interactions of three independent variables (ethanol concentrations [%], microwave power [W], and extraction time [min]) on the dependent variables (total phenolic content [TPC] and antioxidant status via 2,2-diphenyl-1-picrylhydrazyl [DPPH] to establish optimal extraction conditions. The ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) analysis was applied for untargeted metabolite profiling, and in vitro assays were used for evaluation of the antidiabetic and antioxidant potential of the extract. Moreover, an in silico study was used to predict the interaction of five dominant compounds from the UHPLC-Q-TOF-MS profile against the dipeptidyl peptidase-IV (DPP-IV) enzyme.

RESULTS

The optimal conditions for the extraction were established at 60% (v/v) ethanol, 500 W microwave power, and 5 min time with TPC 12.83 ± 0.66 mg GAE/g d.w. and DPPH 45.09 ± 0.07%. The UHPLC-Q-TOF-MS analysis revealed the presence of a total of 106 compounds in the extract. Moreover, the extract prepared through MAE technology presented higher TPC and DPPH findings than the extract prepared through maceration. Similarly, the extract was also found with good antidiabetic activity by inhibiting the DPP-IV enzyme which was also rectified theoretically by a molecular docking study.

CONCLUSION

The current study presents a sustainable and an optimized approach for the preparation of sugarcane bagasse extract with functional phytoconstituents and higher antidiabetic and antioxidant activities.

The association between dietary antioxidant quality score and intensity and frequency of migraine headaches among women: a cross-sectional study

BACKGROUND

Migraine is an episodic disorder and a frequent form of headache. An impaired balance between free radical production and an impaired antioxidant defense system leading to oxidative damage may play a major role in migraine etiology. We sought to investigate whether dietary antioxidant quality score (DAQS) is associated with migraine intensity and frequency among women suffering from migraine.

METHODS

This cross-sectional study was conducted on 265 women. The data related to anthropometric measures and dietary intake were collected. DAQS score was calculated based on FFQ (food frequency questionnaire) vs. the reference daily intake (RDI) quantity. To measure migraine intensity, the migraine disability assessment questionnaire (MIDAS) and visual analog scale (VAS) were used. The frequency of headaches was defined as the days the participants had headaches in the last month and a 30-day headache diary was used.

RESULTS

The results of the study demonstrated that VAS, MIDAS, and frequency of headaches were reduced significantly from the low DAQS (poor quality of antioxidants) to high DAQS (high quality of antioxidants) after adjusting covariates. Also, multinomial regression showed there was an inverse association between higher DAQS and the frequency of headaches. In the adjusted model, subjects with the higher DAQS were 69% less likely to have moderate migraine disability, compared with those with the lower DAQS. Linear regression showed, there was an inverse association between vitamin C intake and the grades of pain severity.َAlso in a crude model, a negative association was found between vitamin E and the frequency of headaches.

CONCLUSION

In conclusion, Participants with higher DAQS had lower migraine intensity and headache frequency. In addition, the consumption of vitamin C may potentially associate with decreasing the severity of headaches. Dietary antioxidants should be monitored closely in individuals suffering from migraine.

Health-Promoting Properties and the Use of Fruit Pomace in the Food Industry-A Review

Fruit pomace, a by-product of the fruit industry, includes the skins, seeds, and pulp most commonly left behind after juice extraction. It is produced in large quantities: apple residues alone generate approximately 4 million tons of waste annually, which is a serious problem for the processing industry but also creates opportunities for various applications. Due to, among other properties, their high content of dietary fiber and polyphenolic compounds, fruit residues are used to design food with functional features, improving the nutritional value and health-promoting, technological, and sensory properties of food products. This article presents the health-promoting (antioxidant, antidiabetic, anti-inflammatory, and antibacterial) properties of fruit pomace. Moreover, the possibilities of their use in the food industry are characterized, with particular emphasis on bread, sweet snack products, and extruded snacks. Attention is paid to the impact of waste products from the fruit industry on the nutritional value and technological and sensory characteristics of these products. Fruit pomace is a valuable by-product whose use in the food industry can provide a sustainable solution for waste management and contribute to the development of functional food products with targeted health-promoting properties.

Galangin: A Promising Flavonoid for the Treatment of Rheumatoid Arthritis-Mechanisms, Evidence, and Therapeutic Potential

Rheumatoid Arthritis (RA) is a chronic autoimmune disease characterized by progressive joint inflammation and damage. Oxidative stress plays a critical role in the onset and progression of RA, significantly contributing to the disease's symptoms. The complex nature of RA and the role of oxidative stress make it particularly challenging to treat effectively. This article presents a comprehensive review of RA's development, progression, and the emergence of novel treatments, introducing Galangin (GAL), a natural flavonoid compound sourced from various plants, as a promising candidate. The bioactive properties of GAL, including its anti-inflammatory, antioxidant, and immunomodulatory effects, are discussed in detail. The review elucidates GAL's mechanisms of action, focusing on its interactions with key targets such as inflammatory cytokines (e.g., TNF-α, IL-6), enzymes (e.g., SOD, MMPs), and signaling pathways (e.g., NF-κB, MAPK), which impact inflammatory responses, immune cell activation, and joint damage. The review also addresses the lack of comprehensive understanding of potential treatment options for RA, particularly in relation to the role of GAL as a therapeutic candidate. It highlights the need for further research and clinical studies to ascertain the effectiveness of GAL in RA treatment and to elucidate its mechanisms of action. Overall, this review provides valuable insights into the potential of GAL as a therapeutic option for RA, shedding light on its multifaceted pharmacological properties and mechanisms of action, while suggesting avenues for future research and clinical applications.

Vitis vinifera L. cv. Falanghina Seed Extracts: Antioxidant Effect of Bioactive Compounds on HepG2 Cells

Vitis vinifera L. is a natural source of bioactive compounds that is already used for cosmeceutical and nutraceutical approaches. However, their phytochemical and antioxidant properties, although studied, have not been fully explored. We aimed to characterize V. vinifera L. cv. Falanghina seed extracts in different polarity solvents (hexane, ethyl acetate, ethanol, and a mixture of acetone-water) for their phytochemical contents, including the total phenolic compound content (TPC), free radical scavenging capacities, and antioxidant ability on HepG2 cells. We directly profiled the functional quality of V. vinifera seed extracts against H2O2-induced oxidative stress in HepG2 cells, focusing on mitochondrial functions. The content of bioactive compounds was characterized by LC-MS. To assess the cytocompatibility of the extracts, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was conducted. Results showed that extraction with ethyl acetate (18.12 mg GAE·g-1) and ethanol solvents (18.07 mg GAE·g-1), through Soxhlet, and with an acetone-water mixture (14.17 mg GAE·g-1), through maceration, yielded extracts rich in (poly)phenols, with good scavenging and antioxidant activity (98.32 I% for ethanol solvents and 96.31 I% for acetone-water mixture). The antioxidant effect of polyphenols is at least partially due to their capacity to maintain mitochondrial biogenesis and mitophagy, which elevates mitochondrial efficiency, resulting in diminished ROS production, hence re-establishing the mitochondrial quality control. These findings highlight the valorization of Vitis by-products to improve food functional characteristics.

Phenolic Compounds from Cherries and Berries for Chronic Disease Management and Cardiovascular Risk Reduction

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide. Therefore, there is increasing interest in dietary interventions to reduce risk factors associated with these conditions. Cherries and berries are rich sources of bioactive compounds and have attracted attention for their potential cardiovascular benefits. This review summarises the current research on the effects of cherry and berry consumption on cardiovascular health, including in vivo studies and clinical trials. These red fruits are rich in phenolic compounds, such as anthocyanins and flavonoids, which have multiple bioactive properties. These properties include antioxidant, anti-inflammatory, and vasodilatory effects. Studies suggest that regular consumption of these fruits may reduce inflammation and oxidative stress, leading to lower blood pressure, improved lipid profiles, and enhanced endothelial function. However, interpreting findings and establishing optimal dosages is a challenge due to the variability in fruit composition, processing methods, and study design. Despite these limitations, the evidence highlights the potential of cherries and berries as components of preventive strategies against CVD. Further research is needed to maximise their health benefits and improve clinical practice.

Insights into metabolic characteristics and biological activity changes in Zangju (Citrus reticulata cv. Manau Gan) peel at different maturity stages through UPLC-MS/MS-based metabolomics

In this study, comprehensive and systematic nontargeted metabolomics analysis was performed with the metabolites of Zangju peel (Citrus reticulata cv. Manau Gan, CRZP, which has been cultivated for over 400 years in Derong County, China.) at four different mature stages. A total of 1878 metabolites were identified, among which flavonoids were the most abundant (62.04 %), and identified 62 key differential metabolites significantly affected by maturity. Based on biological activity measurements, CRZP showed better antioxidant activity, lipase inhibition ability, inhibition of adipogenic differentiation in 3TT-L1 cells and promotion of lipid metabolism, with the biological activity of CRZP at different maturity stages being associated with key differential metabolite. Thus, CRZP is natural antioxidants and possess anti-obesity potential, and industrial production needs to consider the Maturity stage of its collection.

Screening and Characterization of Phenolic Compounds from Selected Unripe Fruits and Their Antioxidant Potential

The food sector's interest in sustainability and the demand for novel bioactive compounds are increasing. Many fruits are wasted every year before ripening due to various climatic conditions and harsh weather. Unripe mangoes, grapes, and black lemons could be rich sources of phenolic compounds that need to be fully elucidated. Using fruit waste as a source of bioactive chemicals has grown increasingly appealing as it may have significant economic benefits. Polyphenols are beneficial for human health to inhibit or minimize oxidative stress and can be used to develop functional and nutraceutical food products. In this context, this study aimed to characterize and screen unripe mangoes, grapes, and black lemons for phenolic compounds using LC-ESI-QTOF-MS/MS and their antioxidant activities. Unripe mangoes were quantified with higher total phenolic content (TPC, 58.01 ± 6.37 mg GAE/g) compared to black lemon (23.08 ± 2.28 mg GAE/g) and unripe grapes (19.42 ± 1.16 mg GAE/g). Furthermore, unripe mangoes were also measured with higher antioxidant potential than unripe grapes and black lemons. A total of 85 phenolic compounds (70 in black lemons, 49 in unripe grapes, and 68 in unripe mango) were identified, and 23 phenolic compounds were quantified using LC-MS/MS. Procyanidin B2, gallic acid, epicatechin, caffeic acid, quercetin, and chlorogenic acid were measured with higher concentration in these selected unripe fruits. A positive correlation was found between phenolic contents and the antioxidant activities of unripe fruits. Furthermore, chemometric analysis was conducted to validate the results. This study will explore the utilization of these unripe fruits to develop functional and therapeutic foods.

2,4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone from Cleistocalyx nervosum var. paniala seeds attenuated the early stage of diethylnitrosamine and 1,2-dimethylhydrazine-induced colorectal carcinogenesis

BACKGROUND

Dichloromethane extract of Cleistocalyx nervosum var. paniala seeds exhibited an anticarcinogenicity against chemically-induced the early stages of carcinogenesis in rats. This study aimed to identify anticarcinogenic compounds from C. nervosum seed extract (CSE).

METHODS

Salmonella mutation assay was performed to determine mutagenicity and antimutagenicity of partially purified and purified compounds of CSE. The anticarcinogenic enzyme-inducing activity was measured in Hepa1c1c7. Moreover, the anticancer potency was examined on various human cancer cell lines. The anticarcinogenicity of DMC was investigated using dual-organ carcinogenicity model. The number of preneoplastic lesions was evaluated in the liver and colon. The inhibitory mechanisms of DMC on liver- and colorectal carcinogenesis were investigated.

RESULTS

Six partially purified fractions (MK1 - MK6) and purified compounds, including 2,4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) and hariganetin, were obtained from CSE. Among these fractions, MK4 and DMC presented the greatest antimutagenicity against indirect mutagens in bacterial model. Moreover, MK5 possessed an effective anticarcinogenic enzyme inducer in Hepa1c1c7. The MK4, DMC and CSE showed greater anticancer activity on all cell lines and exhibited the most effective toxicity on colon cancer cells. Furthermore, DMC inhibited the formation of colonic preneoplastic lesions in carcinogens-treated rats. It reduced PCNA-positive cells and frequency of BCAC in rat colon. DMC also enhanced the detoxifying enzyme, GST, in rat livers.

CONCLUSIONS

DMC obtained from CSE may be a promising cancer chemopreventive compound of colorectal cancer process in rats. It could increase detoxifying enzymes and suppress the cell proliferation process resulting in prevention of post-initiation stage of colorectal carcinogenesis.

Sustainable management of food waste; pre-treatment strategies, techno-economic assessment, bibliometric analysis, and potential utilizations: A systematic review

Food waste (FW) contains many nutritional components such as proteins, lipids, fats, polysaccharides, carbohydrates, and metal ions, which can be reused in some processes to produce value-added products. Furthermore, FW can be converted into biogas, biohydrogen, and biodiesel, and this type of green energy can be used as an alternative to nonrenewable fuel and reduce reliance on fossil fuel sources. It has been demonstrated in many reports that at the laboratory scale production of biochemicals using FW is as good as pure carbon sources. The goal of this paper is to review approaches used globally to promote turning FW into useable products and green energy. In this context, the present review article highlights deeply in a transdisciplinary manner the sources, types, impacts, characteristics, pre-treatment strategies, and potential management of FW into value-added products. We find that FW could be upcycled into different valuable products such as eco-friendly green fuels, organic acids, bioplastics, enzymes, fertilizers, char, and single-cell protein, after the suitable pre-treatment method. The results confirmed the technical feasibility of all the reviewed transformation processes of FW. Furthermore, life cycle and techno-economic assessment studies regarding the socio-economic, environmental, and engineering aspects of FW management are discussed. The reviewed articles showed that energy recovery from FW in various forms is economically feasible.

Valorization of fruit wastes for circular bioeconomy: Current advances, challenges, and opportunities

The demands for fruits and processed products have significantly increased following the surging human population growth and rising health awareness. However, an enormous amount of fruit waste is generated during their production life-cycle due to the inedible portion and perishable nature, which become a considerable burden to the environment. Embracing the concept of "circular economy", these fruit wastes represent sustainable and renewable resources and can be integrated into biorefinery platforms for valorization into a wide range of high-value products. To fully realize the potential of fruit waste in circular bioeconomy and provide insights on future commercial-scale applications, this review presented the recycling and utilization of fruit wastes in various applications, particularly focusing on pollutant bioremediation, renewable energy and biofuel production, biosynthesis of bioactive compounds and low-cost microbial growth media. Furthermore, the challenges of efficient valorization of fruit wastes were discussed and future prospects were proposed.

Suitability of Banana and Plantain Fruits in Modulating Neurodegenerative Diseases: Implicating the In Vitro and In Vivo Evidence from Neuroactive Narratives of Constituent Biomolecules

Active principles in plant-based foods, especially staple fruits, such as bananas and plantains, possess inter-related anti-inflammatory, anti-apoptotic, antioxidative, and neuromodulatory activities. Neurodegenerative diseases affect the functionality of the central and peripheral nervous system, with attendant cognitive deficits being hallmarks of these conditions. The dietary constitution of a wide range of bioactive compounds identified in this review further iterates the significance of the banana and plantain in compromising, halting, or preventing the pathological mechanisms of neurological disorders. The neuroprotective mechanisms of these biomolecules have been identified by using protein expression regulation and specific gene/pathway targeting, such as the nuclear and tumor necrosis factors, extracellular signal-regulated and mitogen-activated protein kinases, activator protein-1, and the glial fibrillary acidic protein. This review establishes the potential double-edged neuro-pharmacological fingerprints of banana and plantain fruits in their traditionally consumed pulp and less utilized peel component for human nutrition.

Ultrasound-Assisted Extraction of High-Value Fractions from Fruit Industrial Processing Waste

This work deals with the valorization of fruit industrial processing waste pretreated with two dehydration methods, air oven and lyophilization. Ultrasound-assisted extraction using a sonication probe was selected to recover the high-value fractions. A battery of experiments following a Box−Behnken design was planned to evaluate the effect of the ultrasound amplitude, extraction duration, and temperature on the yield, protein content, phenolic content, and antiradical capacity of the soluble extracts. Operating at a fixed frequency (24 kHz) and solid:water ratio (1:15), the models predicted (significance degree >95%) the maximum extraction conditions of 69.7% amplitude, 53.43 °C, and 12 min for conventionally dehydrated fruit waste. Under these processing conditions, 52.6% extraction yield was achieved, with a protein content of 0.42 mg/g, total phenolic content of 116.42 mg GAE/g, and antioxidant capacity of 44.95 mg Trolox/g. Similar yields (53.95%) and a notably higher protein content (0.69 mg/g), total phenolic content (135.32 mg GAE/g), and antioxidant capacity (49.52 mg Trolox/g) were identified for lyophilized fruit waste. This treatment required a longer dehydration pretreatment duration (double), higher ultrasound amplitude (80%), and higher extraction temperature (70 °C), but shorter extraction time (4 min). These outcomes highlighted the important impact of the dehydration method on the valorization of the tested waste, with conventional drying saving costs, but the lyophilization procedure enhancing the bioactive features of the waste.

Phenolic Profiling of Berries Waste and Determination of Their Antioxidant Potential

Berries waste is a major issue in Australia’s annual food wastage, which can reach 7.3 million tonnes. This study assessed the phenolic content and antioxidant potential of four fruit berry wastes, including blueberries (Vaccinium corymbosum), blackberries (Rubus spp.), raspberries (Rubus idaeus), and strawberries (Fragaria spp.), followed by their characterization and quantification. Blueberry wastes were high in phenolic content (total phenolic content: 1.97 ± 0.16 mg GAE/gF.W; total flavonoid content: 220.43 ± 13.15 μg QE/gF.W; total tannins content: 16.47 ± 0.98 μg CE/gF.W), and antioxidant potentials are 2,2′-diphenyl-1-picrylhydrazyl: 2.23 ± 0.17 mg AAE/gF.W; 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid): 1.79 ± 0.09 mg AAE/gF.W; ferric reducing antioxidant power: 68.71 ± 11.11 μg AAE/gF.W (total antioxidant capacity: 1.22 ± 0.03 mg AAE/gF.W). The LC-ESI-QTOF-MS/MS analysis identified 87 compounds from blueberry (57), strawberry (40), raspberry (47), and blackberry wastes (27). Indicated by HPLC quantification, blueberry wastes had higher levels of phenolic acid (syringic acid and coumaric acid) and flavonoid (kaempferol and kaempfero l-3-glucoside). Our study reported that phenolics from berry wastes could be utilized in different food, feed, pharmaceutical, and nutraceutical industries.

Agricultural crop waste materials - A potential reservoir of molecules

Crop wastes are one of the agricultural wastes generated during the production and processing of food materials. Their generation is the other side of developmental activities. They are now becoming an alarming source of environmental pollution, leading to an unhealthy society. There is an urgent need to develop robust methods to utilize these types of wastes into beneficial compounds or materials. Many works are successfully done in these areas, and several strategies have been developed to produce biochemicals from biological wastes. In other words, value addition has been done to the crop waste materials. The chemicals like carbohydrates, minerals, proteins, and other compounds have been isolated from various crop residues. In this context, this article covers an overview of the crop wastes, chemicals isolated from them, their extraction methods, and the way forward to get the valuable chemicals.

Biomolecules from Plant Wastes Potentially Relevant in the Management of Irritable Bowel Syndrome and Co-Occurring Symptomatology

During and following the processing of a plant’s raw material, considerable amounts are wasted, composted, or redistributed in non-alimentary sectors for further use (for example, some forms of plant waste contribute to biofuel, bioethanol, or biomass production). However, many of these forms of waste still consist of critical bioactive compounds used in the food industry or medicine. Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The primary treatment is based on symptomatology alleviation and controlled dietary management. Thus, this review aimed to describe the possible relevance of molecules residing in plant waste that can be used to manage IBS and co-occurring symptoms. Significant evidence was found that many forms of fruit, vegetable, and medicinal plant waste could be the source of some molecules that could be used to treat or prevent stool consistency and frequency impairments and abdominal pain, these being the main IBS symptoms. While many of these molecules could be recovered from plant waste during or following primary processing, the studies suggested that enriched food could offer efficient valorization and prevent further changes in properties or stability. In this way, root, stem, straw, leaf, fruit, and vegetable pomaces were found to consist of biomolecules that could modulate intestinal permeability, pain perception, and overall gastrointestinal digestive processes.

Exploring multifunctional antioxidants as potential agents for management of neurological disorders

Free radical or oxidative stress may be a fundamental mechanism underlying several human neurologic diseases. Therapy using free radical scavengers (antioxidants) has the potential to prevent, delay, or ameliorate many neurologic disorders. However, the biochemistry of oxidative pathobiology is complex, and optimum antioxidant therapeutic options may vary and need to be tailored to individual diseases. In vitro and animal model studies support the potential beneficial role of various antioxidant compounds in neurological disease. Antioxidants generally play an important role in reducing or preventing the cell damage and other changes which occur in the cells like mitochondrial dysfunction, DNA mutations, and lipid peroxidation in the cell membrane. Based on their mechanism of action, antioxidants can be used to treat various neurological disorders like Huntington's disease, Alzheimer's disease, and Parkinson's disease. Vitamin E has a scavenging action for reactive oxygen species (ROS) and also prevents the lipid peroxidation. Creatine generally reduces the mitochondrial dysfunction in Parkinson's disease (PD) patients. Various metal chelators are used in PD for the prevention of accumulation of the metals. Superoxidase dismutase (SOD), lipases, and proteases act as repair enzymes in patients with AD. Accordingly, the antioxidant defense system is found to be most useful for treating various neurological disorders.

The ability of deep eutectic solvent systems to extract bioactive compounds from apple pomace

The objective of this study was to examine the bioactivity of extracts from apple pomace obtained by non-conventional green extraction methods (DES systems). Bioactivity was antioxidant capacity and ability to stimulate insulin secretion from pancreatic beta-cells. The antioxidant capacity of extracts was examined using the DPPH and the FRAP assay. Impact of the extracts on cell viability and insulin secretion were examined using the BRIN-BD11 cell line. ChCl:EG(1:4) extracts resulted in high antioxidant capacity in the DPPH assay (80.1% inhibition versus 11.3%). Extracts obtained from the classical systems demonstrated an ability to promote insulin secretion significantly higher than the positive control, p < 0.05. ChCl:EG(1:4) extracts stimulated insulin secretion to a lesser extent. Overall, the data provides evidence for the potential of DES systems to extract bioactive compounds from apple pomace that have relevance for metabolic health. Further optimisation of the extraction procedures should be tailored to the desired bioactive properties.

Antioxidant Properties of Pulp, Peel and Seeds of Phlegrean Mandarin (Citrus reticulata Blanco) at Different Stages of Fruit Ripening

In this work, we assess the potential of waste products of Phlegrean mandarin (Citrus reticulata Blanco), namely seeds and peel, to be reutilized as a source of bioactive compounds beneficial for the human diet. Starting from the evidence that the by-products of this specific cultivar are the most powerful sources of antioxidants compared to pulp, we have investigated if and how the bioactive compounds in peel and seeds may be affected by fruit ripening. Three stages of fruit ripening have been considered in our study: unripe fruits = UF, semi-ripe fruits = SRF, ripe fruits = RF. The overall results indicated that RF showed the highest concentration of antioxidants. Among fruit components, peel was the richest in total antioxidant capacity, total polyphenol content, total flavonoids, total chlorophylls and carotenoids, while seeds exhibited the highest concentration of total condensed tannins and ascorbic acid. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay indicates the occurrence, in peel extracts, of 28 phenolic compounds, mainly flavonoids (FLs); in seeds, 34 derivatives were present in the first stage (UF), which diminish to 24 during the ripening process. Our data indicated that the content of phytochemicals in citrus strongly varies among the fruit components and depends on the ripening stage. The higher antioxidant activity of peel and seeds, especially in RF, encourage a potential use of by-products of this specific citrus cultivar for industrial or pharmacological applications. However, to maximize the occurrence of desired bioactive compounds, it is important also to consider the ripening stage at which fruits must be collected.

Biochar derived from fruit by-products using pyrolysis process for the elimination of Pb(II) ion: An updated review

Water pollution is one of the most concerning global environmental problems in this century with the severity and complexity of the issue increases every day. One of the major contributors to water pollution is the discharge of harmful heavy metal wastes into the rivers and water bodies. Without proper treatment, the release of these harmful inorganic waste would endanger the environment by contaminating the food chains of living organisms, hence, leading to potential health risks to humans. The adsorption method has become one of the cost-effective alternative treatments to eliminate heavy metal ions. Since the type of adsorbent material is the most vital factor that determines the effectiveness of the adsorption, continuous efforts have been made in search of cheap adsorbents derived from a variety of waste materials. Fruit waste can be transformed into valuable products, such as biochar, as they are composed of many functional groups, including carboxylic groups and lignin, which is effective in metal binding. The main objective of this study was to review the potential of various types of fruit wastes as an alternative adsorbent for Pb(II) removal. Following a brief overview of the properties and effects of Pb(II), this study discussed the equilibrium isotherms and adsorption kinetic by various adsorption models. The possible adsorption mechanisms and regeneration study for Pb(II) removal were also elaborated in detail to provide a clear understanding of biochar produced using the pyrolysis technique. The future prospects of fruit waste as an adsorbent for the removal of Pb(II) was also highlighted.

Takakura composting method for food wastes from small and medium industries with indigenous compost

The current work aimed to study the physical, chemical and biological properties of food wastes generated from small and medium industries by using Takakura composting methods. Composting method was referred as indigenous compost (IC) and commercial compost (CC) reactors. The reactors were operated at 44 °C, pH (6 to 8.5) and 40 to 55 % of moisture for 22 weeks in closed environment using a carpet around the basket to avoid external disturbance. The results revealed that the total Kjeldahl nitrogen (TKN), total phosphorus (TP) and potassium (K) in the IC reactors were 6300, 10.57 and 726.07 ppm, respectively, while 8400, 15.45 and 727.81 ppm, respectively, in the CC reactors. Moreover, both IC and CC has Cd2+, Cr2+, Cu2+, Pb2+, Ni2+ and Zn2+ concentrations within the compost legislation standard (CLS). The findings of this study indicated that the composting method could be used as an alternative food waste management in small and medium industry and the Takakura composting method is suitable for food waste composting.

Injectable Lignin-co-Gelatin Cryogels with Antioxidant and Antibacterial Properties for Biomedical Applications

For several biomedical applications, it is essential to develop novel bioactive materials. Such biomaterials could potentially improve wound healing, prevent infections, or be used in immunoengineering. For example, bioactive materials that reduce oxidative stress without relying on antibiotics and other drugs could be beneficial. Hydrogel-based biomaterials, especially those derived from natural polymers, have been regarded as one of the most promising scaffolds for biomedical research. These multifunctional scaffolds can exhibit high water adsorption capacity, biocompatibility, and biomechanical properties that can match native tissues. Cryogels are a special type of hydrogels in which polymers are cross-linked around ice crystals. As a result, cryogels exhibit unique physical features, including a macroporous and interconnected network, flexibility, shape-memory properties, and syringe injectability. Herein, we developed a multifunctional, i.e., antibacterial, antioxidant, and injectable cryogel by combining lignin with gelatin. The cryogel with 0.2% lignin showed a compressive modulus of 25 kPa and a compressive stress of 140 kPa at 80% strain, which is, respectively, 1.8 and 7 times higher than those of the pure gelatin cryogels. Meanwhile, such a cryogel formulation could completely recover its shape after compression up to 90% and was needle-injectable. Additionally, the lignin-co-gelatin cryogel with 0.1-0.2 lignin showed 8-10 mm of inhibition zone against the most common surgical site infection-associated pathogenic bacteria. Furthermore, lignin-co-gelatin cryogel was found to scavenge free radicals and have good cytocompatibility, and the cryogels with up to 0.2% lignin minimally activate naïve mouse bone marrow-derived dendritic cells. Overall, the current approach shows great promise for the design of bioresource-based multifunctional cryogels for a wide range of biomedical applications.

Nobiletin and Xanthohumol Sensitize Colorectal Cancer Stem Cells to Standard Chemotherapy

Simple Summary

Colorectal cancer stem cells (CR-CSCs) play a pivotal role in the therapy resistance and relapse of CRC patients. Herein we demonstrate that new treatment approaches comprising polymethoxyflavones and prenylflavonoids extracted from Citrus sinensis and Humulus lupulus, respectively, hamper the viability of CR-CSCs as well as synergizing with 5-fluorouracil and oxaliplatin (FOX)-based chemotherapy. Extract fractions containing Nobiletin and Xanthohumol, in combination with chemotherapy, decreased stemness properties of CR-CSCs and restrained the outgrowth of chemoresistant metastatic CR-CSCs. These data pinpoint Nobiletin and Xanthohumol as efficacious anti-cancer compounds in metastatic settings.

Abstract

Colorectal cancer (CRC) mortality is mainly caused by patient refractoriness to common anti-cancer therapies and consequent metastasis formation. Besides, the notorious toxic side effects of chemotherapy are a concurrent obstacle to be tackled. Thus, new treatment approaches are needed to effectively improve patient outcomes. Compelling evidence demonstrated that cancer stem cells (CSCs) are responsible for treatment failure and relapse. New natural treatment approaches showed capabilities to selectively target the CSC subpopulation by rendering them targetable by standard cytotoxic compounds. Herein we show the anti-cancer properties of the polymethoxyflavones and prenylflavonoids extracted from Citrus sinensis and Humulus lupulus, respectively. The natural biofunctional fractions, singularly and in combination, reduced the cell viability of CRC stem cells (CR-CSCs) and synergized with 5-fluorouracil and oxaliplatin (FOX) chemotherapy. These phenomena were accompanied by a reduced S and G2/M phase of the cell cycle and upregulation of cell death-related genes. Notably, both phytoextracts in combination with FOX thwarted stemness features in CR-CSCs as demonstrated by the impaired clonogenic potential and decreased Wnt pathway activation. Extracts lowered the expression of CD44v6 and affected the expansion of metastatic CR-CSCs in patients refractory to chemotherapy. Together, this study highlights the importance of polymethoxyflavones and prenylflavonoids as natural remedies to aid oncological therapies.

Influences of Microwave-Assisted Extraction Parameters on Antioxidant Activity of the Extract from Akebia trifoliata Peels

Akebia trifoliata is a fruit with rich nutritional properties, and its peel is produced as a by-product. In this research, we investigated the influences of microwave-assisted extraction parameters on antioxidant activity of the extract from Akebia trifoliata peels, and the ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) as well as total phenolic contents (TPC) were used to optimize extraction parameters. The influences of ethanol concentration, microwave power and solvent-to-material ratio, as well as extraction temperature and time on TPC, FRAP and TEAC values, were assessed using single-factor tests. Three parameters with obvious effects on antioxidant capacity were selected to further investigate their interactions by response surface methodology. The optimal extraction parameters of natural antioxidants from Akebia trifoliata peels were ethanol concentration, 49.61% (v/v); solvent-to-material ratio, 32.59:1 mL/g; extraction time, 39.31 min; microwave power, 500 W; and extraction temperature, 50 °C. Under optimal conditions, the FRAP, TEAC and TPC values of Akebia trifoliata peel extracts were 351.86 ± 9.47 µM Fe(II)/g dry weight (DW), 191.12 ± 3.53 µM Trolox/g DW and 32.67 ± 0.90 mg gallic acid equivalent (GAE)/g DW, respectively. Furthermore, the main bioactive compounds (chlorogenic acid, rutin and ellagic acid) in the extract were determined by high-performance liquid chromatography. The results are useful for the full utilization of the by-product from Akebia trifoliate fruit.

Green extraction techniques from fruit and vegetable waste to obtain bioactive compounds-A review

Food wastes imply significant greenhouse gas emissions, that increase the challenge of climate change and impact food security. According to FAO (2019), one of the main food wastes come from fruit and vegetables, representing 0.5 billion tons per year, of the 1.3 billion tons of total waste. The wastes obtained from fruit and vegetables have plenty of valuable components, known as bioactive compounds, with many properties that impact positively in human health. Some bioactive compounds hold antioxidant, anti-inflammatory, and anti-cancer properties and they have the capacity of modulating metabolic processes. Currently, the use of fruit and vegetable waste is studied to obtain bioactive compounds, through non-conventional techniques, also known as green extraction techniques. These extraction techniques report higher yields, reduce the use of solvents, employ less extraction time, and improve the efficiency of the process for obtaining bioactive compounds. Once extracted, these compounds can be used in the cosmetic, pharmaceutical, or food industry, the last one being focused on improving food quality.

The Prospects of Agricultural and Food Residue Hydrolysates for Sustainable Production of Algal Products

The growing demand of microalgal biomass for biofuels, nutraceuticals, cosmetics, animal feed, and other bioproducts has created a strong interest in developing low-cost sustainable cultivation media and methods. Agricultural and food residues represent low-cost abundant and renewable sources of organic carbon that can be valorized for the cultivation of microalgae, while converting them from an environmental liability to an industrial asset. Biochemical treatment of such residues results in the release of various sugars, primarily glucose, sucrose, fructose, arabinose, and xylose along with other nutrients, such as trace elements. These sugars and nutrients can be metabolized in the absence of light (heterotrophic) or the presence of light (mixotrophic) by a variety of microalgae species for biomass and bioproduct production. The present review provides an up-to-date critical assessment of the prospects of various types of agricultural and food residues to serve as algae feedstocks and the microalgae species that can be grown on such residues under a range of cultivation conditions. Utilization of these feedstocks can create potential industrial applications for sustainable production of microalgal biomass and bioproducts.

Strategies to Improve the Thermo-Oxidative Stability of Sunflower Oil by Exploiting the Antioxidant Potential of Blueberries Processing Byproducts

This research was conducted in order to establish the effectiveness of two freeze-dried extracts obtained from blueberry processing byproducts resulting from juice manufacturing compared to butylated hydroxytoluene (BHT) in delaying the lipid oxidation of sunflower oil subjected to high-temperature convective heating at 180 °C up to 12 h under simulated frying conditions. The fruits were harvested from spontaneous flora of two regions of Romania, Arieseni (Alba County) and Paltinis (Sibiu County) and the blueberry byproducts extracts (BBE) were noted according to the origin place as ABBE and PBBE. The progress of lipid thermo-oxidation was investigated in terms of peroxide value (PV), p-anisidine value (p-AV), the response of TBA-malondialdehyde interactions assessed by thiobarbituric acid (TBA) method, the total oxidation (TOTOX) value and inhibition of oil oxidation (IO). The recorded data highlighted that BBE exhibit a high inhibitory response on lipid thermo-oxidation. The inhibitory effect was concentration-dependent, thus, the degree of lipid oxidation was in reverse related to the BBE dose. The exposure of the oil samples supplemented with 800 ppm BBE (ABBE, PBBE) to a high-temperature heating for 12 h led to a significant decrease of the assessed indices compared to additives-free sunflower oil sample as follows: PV (46%; 45%), p-AV (21%; 17%), TOTOX (27%; 24%), TBA value (25%; 11%). Regarding the impact of the origin on the potential of BBE to inhibit the lipid oxidative degradation, it was noted that ABBE derived from blueberries grown in a region with a milder climate with moderate precipitations and higher temperatures showed a stronger inhibitory effect on lipid thermo-oxidation than PBBE. A moderate level of 500 ppm BBE inhibited the lipid oxidation similar to 200 ppm BHT. The reported results reveal that BBE represent efficient natural antioxidants that could be successfully applied to improve the thermo-oxidative stability of sunflower oil used in various high-temperature food applications.

Optimization of extraction of loquat flowers polyphenolics and its antioxidant and anti-polyphenol oxidase properties

In this study, the conditions of extraction of loquat flowers polyphenolics were optimized through response surface methodology (RSM). Proper extraction conditions were: solid to liquid ratio 1 g per 50 mL and ethanol concentration 50% at 61°C for 9 min. Furthermore, the antioxidant and anti-polyphenol oxidase (PPO) activity of purified total polyphenolics (PTP) were investigated. PTP displayed strong antioxidant activity with IC50 values of 126.3 ± 8.9, 162.4 ± 6.3 and 94.97 mg ascorbic acid equivalent/g dry weight (mg AAE/d.w.) for ABTS, DPPH, and FRAP assays. In addition, PTP has a substantial inhibitory activity on PPO (IC50 = 115 ± 9.2 μg/mL). From the kinetics analysis, it was proved to be a reversible and mixed-type inhibitor of PPO with KI and KIS values of 76.77 μg/mL and 227.86 μg/mL, respectively. Further, the molecular mechanism underlying the inhibition of PPO by PTP was investigated by molecular docking techniques. The results showed that PTP units could form interaction with the catalytic pocket of PPO through the interaction with amino acid residues in the enzyme active center. The antioxidant activities of PTP together with its effect on PPO activity provide a strong starting point for their practical usage in the food industry.

Extraction and Characterization of Antioxidant Peptides from Fruit Residues

Fruit residues with high protein contents are generated during the processing of some fruits. These sustainable sources of proteins are usually discarded and, in all cases, underused. In addition to proteins, these residues can also be sources of peptides with protective effects against oxidative damage. The revalorization of these residues, as sources of antioxidant peptides, requires the development of suitable methodologies for their extraction and the application of analytical techniques for their characterization. The exploitation of these residues involves two main steps: the extraction and purification of proteins and their hydrolysis to release peptides. The extraction of proteins is mainly carried out under alkaline conditions and, in some cases, denaturing reagents are also employed to improve protein solubilization. Alternatively, more sustainable strategies based on the use of high-intensity focused ultrasounds, microwaves, pressurized liquids, electric fields, or discharges, as well as deep eutectic solvents, are being implemented for the extraction of proteins. The scarce selectivity of these extraction methods usually makes the subsequent purification of proteins necessary. The purification of proteins based on their precipitation or the use of ultrafiltration has been the usual procedure, but new strategies based on nanomaterials are also being explored. The release of potential antioxidant peptides from proteins is the next step. Microbial fermentation and, especially, digestion with enzymes such as Alcalase, thermolysin, or flavourzyme have been the most common. Released peptides are next characterized by the evaluation of their antioxidant properties and the application of proteomic tools to identify their sequences.

Optimization of the Recovery of Anthocyanins from Chokeberry Juice Pomace by Homogenization in Acidified Water

ABSTRACT

The recovery efficiency of waste valorization processes depends on an interplay of different conditions that are sometimes overlooked. Process optimization by the means of establishing mathematical relations between the process parameters and outputs is a strong tool to identify optimal operating conditions based on experimental data. In this study, the extraction of anthocyanins from chokeberry (Aronia melancocarpa) juice pomace using homogenization in acidified water was selected as a case study for process optimization using response surface methodology. The parameters studied were the citric acid content in the water, the temperature and the liquid-solid ratio. The optimal conditions to maximize both anthocyanin concentration and total anthocyanin content extracted were 1.5 wt% citric acid, 45 °C and 34 g solvent/g fresh pomace. Furthermore, the model developed predicted satisfactorily the overall anthocyanin content and anthocyanin concentration in the extract, as well as the final pH and total dissolved solids. The process optimization performed in this study sets the ground for further process design targeting the production of high-value products from byproducts or biowaste to be used in food ingredients or supplements.

Comparative Studies on Different Citrus Cultivars: A Revaluation of Waste Mandarin Components

Peel, pulp and seed extracts of three mandarin varieties, namely Phlegraean mandarin (Citrus reticulata), Kumquat (Citrus japonica), and Clementine (Citrus clementina) were compared and characterised in terms of photosynthetic pigment content, total polyphenols amount, antioxidant activity and vitamin C to assess the amount of functional compounds for each cultivar. The highest polyphenols content was found in the Phlegraean mandarin, especially in peel and seeds, whereas Kumquat exhibited the highest polyphenols amount in the pulp. The antioxidant activity was higher in the peel of Phlegraean mandarin and clementine compared to Kumquat, which showed the highest value in the pulp. The antioxidant activity peaked in the seeds of Phlegraean mandarin. The vitamin C in the Phlegraean mandarin was the highest in all parts of the fruit, especially in the seeds. Total chlorophyll content was comparable in the peel of different cultivars, in the pulp the highest amount was found in clementine, whereas kumquat seeds showed the greatest values. As regards total carotenoids, peel and pulp of clementine exhibited higher values than the other two cultivars, whereas the kumquat seeds were the richest in carotenoids. Among the analysed cultivars Phlegraean mandarin may be considered the most promising as a source of polyphenols and antioxidants, compared to the clementine and Kumquat, especially for the functional molecules found in the seeds. Moreover, regardless of cultivars this study also highlights important properties in the parts of the fruit generally considered wastes.

Advances and Prospects of Phenolic Acids Production, Biorefinery and Analysis

Biotechnological production of phenolic acids is attracting increased interest due to their superior antioxidant activity, as well as other antimicrobial, dietary, and health benefits. As secondary metabolites, primarily found in plants and fungi, they are effective free radical scavengers due to the phenolic group available in their structure. Therefore, phenolic acids are widely utilised by pharmaceutical, food, cosmetic, and chemical industries. A demand for phenolic acids is mostly satisfied by utilising chemically synthesised compounds, with only a low quantity obtained from natural sources. As an alternative to chemical synthesis, environmentally friendly bio-based technologies are necessary for development in large-scale production. One of the most promising sustainable technologies is the utilisation of microbial cell factories for biosynthesis of phenolic acids. In this paper, we perform a systematic comparison of the best known natural sources of phenolic acids. The advances and prospects in the development of microbial cell factories for biosynthesis of these bioactive compounds are discussed in more detail. A special consideration is given to the modern production methods and analytics of phenolic acids.

Extraction and characterization of pectin methylesterase from muskmelon biowaste for pectin remodeling

Pectin methylesterase (PME) extracted from muskmelon was purified by anion exchange chromatography. The specific activity of purified enzyme was 152.01 U/mg and relative molecular weight was ~69,000 Da. Methylesterase was characterized for various physicochemical factors to designate its suitability in the food industry applications. The optimum temperature of the enzyme was 30°C and is thermally stable between the temperature ranges of 15-65°C with critical temperature for stability being >65°C. Thermal inactivation first order kinetics and thermodynamic parameters in temperature range (45-65°C) favors stability of PME and at 75°C complete inactivation of enzyme was observed indicating the unstable nature of enzyme over >65°C. Activation energy (E_a ) and Z values of thermal inactivation were found to be 100.108 kJ/mol and 2.05°C, respectively. About 0.1 M NaCl is essential for enzyme to attain the maximum activity. The enzyme lost activity in presence of divalent calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) ions. PRACTICAL APPLICATIONS: Pectin methylesterase (EC3.1.1.11) are an important class of enzymes expressed in plants and microbes and they bring about the de-methylesterification on pectin substrate. Up to ~13% degree of esterification of pectin was observed with muskmelon PME enzyme treatment. The de-methylesterified pectin thus prepared was subjected for gelation in presence of Ca²⁺ ions and above 0.5% of demethylesterified pectin stable calcium pectate gels were produced. The study demonstrates the suitability of muskmelon PME extracted from biowaste in food applications with good gelling property.

Improvement of Mineral Absorption and Nutritional Properties of Citrullus vulgaris Seeds Using Solid-State Fermentation

Objective: Citrullus vulgaris seeds are the most concealed oil seeds consist of vital therapeutic potential. Apart from nutritional and therapeutic indices, these seeds contain numerous anti-nutritional components.Method: Hence, solid-state fermentation was used as an alternative biotechnological contrivance to enhance the nutritional and functional properties of seeds. Fungal strain Aspergillus awamori was used for solid-state fermentation and uncoated watermelon seeds were used as a substrate for 144h. The range of bulk density was obtained from 0.39 to 0.72 g/cm³, however, fermentation significantly decreased the bulk density of the seed flours. Based upon soluble nitrogen content (79.81%) and functional properties, fermented seed samples of 120h was selected for FTIR analysis and in-vitro mineral bioavailability through Caco-2 cells.Results: FTIR spectrum confirmed the presence of amide groups (1200-1100 cm^-1) of the protein.Conclusion: Fermented seeds also unveiled significantly (p<0.05) higher iron (61.24%), zinc (62.36%), and calcium (61.89%) bioavailability and this significant increase in bioavailability confirmed significantly (p<0.05) higher cellular mineral uptake.

Reuse of Food Waste and Wastewater as a Source of Polyphenolic Compounds to Use as Food Additives

The problem of waste and byproducts generated from agro-industrial activities worldwide is an increasing concern in terms of environmental sustainability. In this ambit, the quantity of food wastes—produced in all steps of the whole food chain—is enormous, and it may be forecasted that food waste could amount to more than 120 billion tonnes by 2020. The reuse of food waste and wastewater as source of polyphenolic compounds could be an interesting discussion in this ambit. In fact, polyphenols obtained in this way might be used for food and non-food purposes by means of new, improved, and safe extraction methods. In light of the opportunity represented by the treatment of agro-industrial waste, different systems concerning the winemaking and olive oil production industries have also been discussed as describing approaches applicable to other sectors. More research is needed before considering recovery of phenolic compounds from wastewater as an economically convenient choice for the food sector.

A Critical Review on Tropical Fruits Seeds as Prospective Sources of Nutritional and Bioactive Compounds for Functional Foods Development: A Case of Indonesian Exotic Fruits

Some tropical countries in the Southeast Asia are rich in exotic fruits with worldwide acceptance, such as mango, orange, snake fruit, durian, jackfruit, rambutan, and avocado. In addition to their abundant production, those fruits are also currently gaining expansive distribution and marketing due to their promising advantages to human well-being. Surprisingly, their by-products, especially the seed kernel and peel, which account about 10-35% of their weight also offer high nutritional and functional potentials. This work exhibits the nutritional and bioactive compositions of the seeds of eight tropical exotic fruits, which are analyzed for their possible application as sources of functional food and environmental points of view. The seeds contain essential bioactive components, such as polyphenols, flavonoids, phenolic acid, and carotenoids, that exhibit excellent antioxidant activity, fats that have remarkable physicohemical properties (free of trans-fatty acids), and a high protein content. After a proper reduction of antinutritional contents, seed powders which contain carbohydrate, protein, and premium lipids or specific extracts with excellent functional properties can be obtained. However, further research should be carried out to determine the profiles of the nutritional and bioactive components in different seed types, their bioavailability, and their efficacy. Extensive researches with the industrial parts should also be performed to valorize the nutritional and functional potentials of these exotic fruit seeds.

Chemical Composition and Biological Activities of Extracts from Pomelo Peel By-Products under Enzyme and Ultrasound-Assisted Extractions

Enzyme-assisted extraction (EAE) and ultrasound-assisted extraction (UAE) were popular methods used to extract bioactive compounds from citrus peels, by-products of fruit processing industry. In this study, the total phenolic content (TPC), total flavonoid content (TFC), naringin and hesperidin contents, and antioxidant and antimicrobial activities of the extracts from pomelo peels using the combined enzyme and ultrasound-assisted extraction (E-UAE) or ultrasound and enzyme-assisted extraction (U-EAE) technique were investigated and compared with those extracted using the EAE and UAE. The optimal EAE conditions were as follows: enzyme concentration of 2%, water-solid ratio of 40 ml/g, incubation temperature of 50°C, and extraction time of 60 min, whereas the optimal UAE conditions were ultrasonic energy of 40 kHz, water-solid ratio of 40 ml/g at room temperature, and extraction time of 60 min. The results indicate that the total phenolics, total flavonoids, naringin, and hesperidin contents of the extracts significantly increased in the following order of the extraction techniques: UAE < EAE < U-EAE < E-UAE (p<0.05). The combined E-UAE technique was the most effective technique for bioactive compound extraction with the highest antioxidant and antimicrobial activities. The results also indicate that chemical composition and antioxidant and antimicrobial activities of the extracts were different depending on the pomelo species.

Valorization of byproducts from tropical fruits: Extraction methodologies, applications, environmental, and economic assessment: A review (Part 1: General overview of the byproducts, traditional biorefinery practices, and possible applications)

Tropical fruits represent one of the most important crops in the world. The continuously growing global market for the main tropical fruits is currently estimated at 84 million tons, of which approximately half is lost or wasted throughout the whole processing chain. Developing novel processes for the conversion of these byproducts into value-added products could provide a viable way to manage this waste problem, aiming at the same time to create a sustainable economic growth within a bio-economy perspective. Given the ever-increasing concern about sustainability, complete valorization through a bio-refinery approach, that is, zero waste concept, as well as the use of green techniques is therefore of utmost importance. This paper aims to report the status on the valorization of tropical fruit byproducts within a bio-refinery frame, via the application of traditional methodologies, and with specific attention to the extraction of phenolics and carotenoids as bioactive compounds. The different types of byproducts, and their content of bioactives is reviewed, with a special emphasis on the lesser-known tropical fruits. Moreover, the bioactivity of the different types of extracts and their possible application as a resource for different sectors (food, pharmaceutical, and environmental sciences) is discussed. Consequently, this review presents the concepts of tropical fruit biorefineries, and the potential applications of the isolated fractions.