Valorization of melon fruit (Cucumis melo L.) by-products: Phytochemical and Biofunctional properties with Emphasis on Recent Trends and Advances

Effects of derivatization and probiotic transformation on the antioxidative activity of fruit polyphenols

Fruits contain numerous polyphenols in the form of conjugates, which exhibit low antioxidant activity. Probiotic fermentation is a strategy to improve the antioxidant activity of these conjugated polyphenols by modifying their structure. However, the mechanisms underlying the effects of functional groups and derivatizations on the antioxidative activities of polyphenols and the antioxidation enhancement by probiotic biotransformation haven't been comprehensively explored. This review aimed to explore the structure-antioxidant activity relationships of four functional groups and three derivatizations in flavonoids and phenolic acids. Further, the review elucidated the antioxidant mechanisms underlying the biotransformation of flavonoids and phenolic acids as glycoside, methylated, and ester conjugates by probiotic biotransformation. Deglycosylation, demethylation, and hydrolysis catalyzed by enzymes produced by Bifidobacterium and Lactobacillus facilitated the conversion of conjugated polyphenols into flavonoids and phenolic acids with hydrolyzed forms and highly active functional groups, thereby increasing hydrogen supply and electron transfer capacity to enhance the antioxidant activity.

The Influence of Maceration and Flavoring on the Composition and Health-Promoting Properties of Roasted Coffee

Over the years, many methods of refining green beans have been developed, including maceration aimed at enriching the coffee aroma and improving the overall quality. This study aimed to evaluate the influence of different methods of maceration (fruit and wine) and the addition of food flavors to coffee beans on antioxidant activity, caffeine, phenolic and organic acid content, as well as health-promoting properties. This research showed that the use of the maceration in melon and apple fruit pulp (100 g of fruit pulp per 100 g of green coffee, incubated for 24 h, coffee roasting at 230 °C, control trial roasted coffee) ensured the highest polyphenol (hydroxycinnamic acids and their esters-chlorogenic acids) content (in melon pulp-13.56 g/100 g d.b. (dry bean); in apple pulp-13.22 g/100 g d.b., p < 0.05 (one-way ANOVA)) and antioxidant activity. Melon (92.11%, IC50 = 3.80 mg/mL extract) and apple (84.55%, IC50 = 4.14 mg/mL) showed the highest α-amylase (enzyme concentration 10 μmol/mL) inhibition activity (0.5 mg/mL for both fruits). The addition of food flavors reduced the total content of chlorogenic acids to the range of 4.64 to 6.48 g/100 g d.b. and increased the content of acrylamide and 5-HMF, which positively correlated with a low antioxidant potential compared to the macerated samples and the control. Studies have shown that coffee macerated in the pulp of melon and apple fruit, due to its great potential to inhibit α-amylase in vivo, may have a preventive effect on type II diabetes. This study complements the current knowledge on the potential health-promoting properties of coffee flavored using different methods; further research should include more advanced models for testing these health-promoting properties. Statistical analysis was based on the determination of the average values of six measurements and their standard deviation, as well as on the one-way ANOVA (analysis of variation) and the Pearson correlation coefficient, using Statistic 10.0 software. The significance was defined at p ≤ 0.05.

Characterization and stress-responsive regulation of CmPHT1 genes involved in phosphate uptake and transport in Melon (Cucumis melo L.)

BACKGROUND

Phosphorus (P) deficiency, a major nutrient stress, greatly hinders plant growth. Phosphate (Pi) uptake in plant roots relies on PHT1 family transporters. However, melon (Cucumis melo L.) lacks comprehensive identification and characterization of PHT1 genes, particularly their response patterns under diverse stresses.

RESULTS

This study identified and analyzed seven putative CmPHT1 genes on chromosomes 3, 4, 5, 6, and 7 using the melon genome. Phylogenetic analysis revealed shared motifs, domain compositions, and evolutionary relationships among genes with close histories. Exon number varied from 1 to 3. Collinearity analysis suggested segmental and tandem duplications as the primary mechanisms for CmPHT1 gene family expansion. CmPHT1;4 and CmPHT1;5 emerged as a tandemly duplicated pair. Analysis of cis-elements in CmPHT1 promoters identified 14 functional categories, including putative PHR1-binding sites (P1BS) in CmPHT1;4, CmPHT1;6, and CmPHT1;7. We identified that three WRKY transcription factors regulated CmPHT1;5 expression by binding to its W-box element. Notably, CmPHT1 promoters harbored cis-elements responsive to hormones and abiotic factors. Different stresses regulated CmPHT1 expression differently, suggesting that the adjusted expression patterns might contribute to plant adaptation.

CONCLUSIONS

This study unveils the characteristics, evolutionary diversity, and stress responsiveness of CmPHT1 genes in melon. These findings lay the foundation for in-depth investigations into their functional mechanisms in Cucurbitaceae crops.

Obtention and Characterization of Microcrystalline Cellulose from Industrial Melon Residues Following a Biorefinery Approach

Residual melon by-products were explored for the first time as a bioresource of microcrystalline cellulose (MCC) obtention. Two alkaline extraction methods were employed, the traditional (4.5% NaOH, 2 h, 80 °C) and a thermo-alkaline in the autoclave (2% NaOH, 1 h, 100 °C), obtaining a yield of MCC ranging from 4.76 to 9.15% and 2.32 to 3.29%, respectively. The final MCCs were characterized for their chemical groups by Fourier-transform infrared spectroscopy (FTIR), crystallinity with X-ray diffraction, and morphology analyzed by scanning electron microscope (SEM). FTIR spectra showed that the traditional protocol allows for a more effective hemicellulose and lignin removal from the melon residues than the thermo-alkaline process. The degree of crystallinity of MCC ranged from 51.51 to 61.94% and 54.80 to 55.07% for the thermo-alkaline and traditional processes, respectively. The peaks detected in X-ray diffraction patterns indicated the presence of Type I cellulose. SEM analysis revealed microcrystals with rough surfaces and great porosity, which could remark their high-water absorption capacity and drug-carrier capacities. Thus, these findings could respond to the need to valorize industrial melon by-products as raw materials for MCC obtention with potential applications as biodegradable materials.

Hybridization Between the Canary Melon and a Vietnamese Non-sweet Melon Cultivar Aiming to Improve the Growth Performance and Fruit Quality in Melon (Cucumis melo L.)

Canary melon has been widely consumed as a dessert fruit due to its fragrance, sweetness, and flavorful taste. However, the cultivation of this cultivar has been challenged in Vietnam because of its weak growth performance and high susceptibility to local pathogens. In this study, we aim to generate the hybrid melon lines between the Canary melon and a local non-sweet melon that are expected to produce good quality fruits as well as to show better growth performance in the local cultivation conditions. Two crossing pairs including (1) MS hybrid (♂ non-sweet melon × ♀ Canary melon) and (2) MN-S hybrid (♂ Canary melon × ♀ non-sweet melon) were carried out and two hybrid lines were subsequently obtained. Next, different phenotypic and physiological parameters such as stem length, stem diameter, 10th leaf diameter, fruit size, fruit weight, and fruit sweetness (pH, °Brix, and soluble sugar contents) were examined and compared between the parental lines (Canary melon and non-sweet melon) and the hybrid lines (MS and MN-S). The results showed that the stem length and fruit size and weight of MS and MN-S hybrids were higher than those of Canary melon. Basically, the content of sugars (sucrose, glucose, and fructose) is a primary and important factor in determining the sweetness of the melon. The pH, °Brix, sucrose and glucose contents of MS hybrid and Canary melon fruits were higher in comparison to MN-S and non-sweet melon fruits. Accordingly, the transcript levels of different sugar metabolism-related genes including SUCROSE SYNTHASE 1 (SUS1), SUS2, UDPGLC EPIMERASE 3 (UGE3), and SUCROSE-P SYNTHASE 2 (SPS2) were examined in all studied lines. In the fruits, the expression levels of these genes were found to be highest in the Canary melon, average in the MS hybrid, and relatively low in the MN-S hybrid and non-sweet melons. Taken together, the heterosis in terms of plant and fruit size was obviously observed in this crossing approach. The relatively high fruit sweetness in the MS hybrid (the mother is Canary melon) also implies that the choice of the mother for crossing is very important since it can determine the fruit quality of the offspring.

Importance of Certain Varieties of Cucurbits in Enhancing Health: A Review

The Cucurbitaceae family is an extensive group of fruits and vegetables that exhibit common characteristics; for example, they are farmed on a global scale and exhibit a wide range of applications, including fresh consumption and use in various food and beverage products. As is frequent, many species or genera share a common name, and this can lead to some confusion when looking for information about a specific variety. In this review, we describe the findings about the biological activity, like antibacterial, antiviral, antidiabetic, and anticancer properties, of two genera of this family, Cucumis and Momordica, which have been characterized and evaluated in several research studies and regarding which information is readily accessible. Those activities rely on the various physicochemical qualities and nutritional content of each variety, including factors like β-carotene and polyphenols, among others. The goal of this review is to provide a rapid search for each activity examined in the literature, enabling future research on their potential uses in functional foods and nutraceutical supplements.

Cardioprotective and hypotensive mechanistic insights of hydroethanolic extract of Cucumis melo L. kernels in isoprenaline-induced cardiotoxicity based on metabolomics and in silico electrophysiological models

Background: Cardiovascular diseases (CVD) continue to threaten health worldwide, and account for a significant portion of deaths and illnesses. In both developing and industrialized nations, they challenge their health systems. There are several traditional uses of Cucurbitaceae seeds in Pakistan, India, Iran, and China, including treating cardiovascular, neurological, and urogenital diseases. Methods: In the present work, integrated techniques of metabolomics profiling and computational cardiomyocyte stimulation were used to investigate possible mechanisms of C. melo in isoprenaline (ISO)-induced myocardial infarction. In vitro, vasoconstrictions, paired atria, and in vivo invasive blood pressure measurement models were performed to explore the mechanism of action of C. melo hydroethanolic seed extract (Cm-EtOH). Results: Results showed that Cm-EtOH demonstrates NO-based endothelium-derived relaxing factor (EDRF) vasorelaxant response, negative chronotropic and inotropic response in the atrium, and hypotensive effects in normotensive rats. Results also revealed that Cm-EtOH decreases cardiomyocyte hypertrophy and reverts the altered gene expressions, biochemical, and metabolites in ISO-induced myocardial infarction (MI) rats. The extract additionally reversed ISO-induced MI-induced oxidative stress, energy consumption, and amino acid metabolism. Moreover, C. melo seeds increased EDRF function, energy production, and antioxidant capacity to treat myocardial and vascular disorders. In computational cardiomyocyte simulation, gallic acid reduced action potential duration, upstroke velocity (dV/dtmax), and effective refractory period. Conclusion: This study highlights the therapeutic potential of C. melo seeds to treat cardiovascular diseases and provides mechanistic insight into its antihypertensive and cardioprotective activities.

Free and Bound Phenolic Profiles and Antioxidant Activities in Melon (Cucumis melo L.) Pulp: Comparative Study on Six Widely Consumed Varieties Planted in Hainan Province

Bound phenolic compounds in the melon pulp have seldom been investigated. This study revealed considerable differences in the total phenolic content (TPC) and antioxidant activity of the free and bound phenolic extracts in the pulps of six melon varieties from Hainan Province, China. Naixiangmi and Yugu demonstrated the highest free TPC, while Meilong showed the highest bound and total TPC and antioxidant activity. UHPLC-QQQ-MS identified and quantified 30 phenolic compounds. The melon cultivars markedly differed in the amount and content of their free and bound phenolic compounds. Xizhoumi No. 25 and Meilong afforded the most phenolic compounds. Hongguan emerged with the highest free phenolic compound content and total content of phenolic compounds; however, Meilong possessed the highest bound phenolic compound content. Hierarchical cluster analysis divided the melon varieties into four different taxa. The present study provides a scientific basis for developing the health-promoting effects of melon pulp.

Effect of high hydrostatic pressure on aroma volatile compounds and aroma precursors of Hami melon juice

High hydrostatic pressure (HHP) treatment is an effective technique for processing heat-sensitive fruits and causes changes in volatile compounds and their precursors while maintaining quality. We investigated the changes and correlations of volatile compounds, related enzyme activities and precursor amino acids, and fatty acids in Hami melon juice under 350-500 MPa pressure. The application of HHP treatment resulted in a considerable reduction of esters and a substantial increase in aldehydes and alcohols in C6 and C9. Activities of lipoxygenase (LOX), alcohol acyltransferase (AAT), and phospholipase A2 (PLA2) were lower than those of the untreated group, alcohol dehydrogenase (ADH) activity was reversed. When compared to fresh cantaloupe juice, there was an increase in both the types and contents of amino acids with lower total fatty acid contents than the control group. Positive correlations were observed among six ester-related substances and eight alcohol-related substances. Additionally, the correlations between volatile compounds and fatty acids were more substantial compared to those between volatile compounds and amino acids. HHP treatment increases Hami melon flavor precursors and is an effective way to maintain the aroma volatile compounds and flavor of Hami melon juice.

Effect of Cucumis melo L. peel extract supplemented postbiotics on reprograming gut microbiota and sarcopenia in hindlimb-immobilized mice

Postbiotics made from lactic acid bacteria may ameliorate sarcopenia via the metabolic reprogramming of gut dysbiosis. This study investigated the anti-sarcopenic effect of postbiotics (WDK) produced from polyphenol-rich melon peel extract (Cucumis melo L. var. makuwa, KEE) and whey with Lentilactobacillus kefiri DH5 (DH5) in C2C12 skeletal muscle cells and hindlimb-immobilized mice. WDK significantly ameliorated palmitate-induced atrophy of C2C12 cells, restoring myotube length and diameter. It also upregulated the expression of myogenic genes including Atrogin-1, Igf-1, and MyoD. Hindlimb-immobilized C57BL/6J mice were randomly divided and orally administered 10 mL/kg body weight of saline (CON), Whey, Whey + DH5 (WD), DH5 + KEE, Whey + DH5 + KEE postbiotic (WDK) for three weeks (n = 10/group). Interestingly, WDK significantly improved muscle function in hindlimb-immobilized mice by restoring both the grip strength and the mass of the soleus muscle, which was closely related to the upregulation of the myoD gene. WDK increased microbial diversity and modulated the distribution of intestinal bacteria, particularly those involved in protein synthesis and the production of butyrate. There was a significant correlation between myogenic biomarkers and butyrate producing gut microbiota. Restoration of muscle mass and function following postbiotic WDK is strongly related to the regulation of myogenic genes by in part remodulating gut microbiota. In conclusion, these findings suggest that polyphenol- and whey-based postbiotics WDK may have potential as an effective manner to combat the progression of sarcopenia.

Cashew By-Product as a Functional Substrate for the Development of Probiotic Fermented Milk

Cashew (Anacardium occidentale) processing generates a by-product (CB) with potential for health benefits and that could be a favorable ingredient to be added to a probiotic food matrix. This study aimed to assess the functional attributes of CB in fermented milk with a probiotic and a starter culture using in vitro gastrointestinal conditions. Two formulations were tested, without CB (Control Formulation-CF) and with CB (Test Formulation-TF), and the two strains most adapted to CB, the probiotic Lacticaseibacillus paracasei subsp. paracasei F19® and the starter Streptococcus thermophilus ST-M6®, were chosen to be fermented in the CF and the TF. During a 28-day period of refrigeration (4 °C), both strains used in the CF and TF maintained a population above 8.0 log CFU/mL. Strains cultured in the TF had a significant increase in total phenolic compounds and greater antioxidant potential during their shelf life, along with improved survival of F19® after in vitro-simulated gastrointestinal conditions. Our study revealed the promising potential of CB in the probiotic beverage. The CB-containing formulation (TF) also exhibited higher phenolic content and antioxidant activity. Furthermore, it acted as a protector for bacteria during gastrointestinal simulation, highlighting its potential as a healthy and sustainable product.

Natural Antioxidant Potential of Melon Peels for Fortified Foods

Agricultural and food waste recycling reduces natural resource losses, contributing significantly to the development of new green markets through the creation of redesigned products. In order to cycle valuable molecules, the peels from Italian cantaloupe (Cucumis melo L.) cultivars were studied and successfully characterized for high-added biomolecules to verify their possible exploitation as wealthy biomasses. Peels were investigated for their cell wall-modifying and browning enzymes, as well as for total polyphenols, ortho-diphenols, flavonoids, tannins, and antioxidant properties. The results of the analyses displayed great promise in one of the three cultivars investigated. Later on, a preliminary study using the best peel extract as a dietary supplement was carried out by preparing fortified seawater to enhance its antioxidant power. The effects of storage time (60 days) were examined at two temperatures through the determination of the stability of the polyphenol content. The kinetic parameters of degradation were also calculated. The "enriched sea water" retained great antioxidant activity in refrigerated conditions, demonstrating that there is good potential for melon by-products to add their natural compounds for food fortification. These findings may provide valuable data for scale-up, from the lab to the pilot or industrial application.

Nano- and Micro-Encapsulation of Long-Chain-Fatty-Acid-Rich Melon Seed Oil and Its Release Attributes under In Vitro Digestion Model

Melon seed oil (MSO) possesses plenty of long-chain fatty acids (LFCAs, oleic-linoleic acid 90%), remarkable antioxidant activity (DPPH (0.37 ± 0.40 µmol TE/g), ABTS (4.98 ± 0.18 µmol TE/g), FRAP (0.99 ± 0.02 µmol TE/g), and CUPRAC (4.94 ± 0.11 µmol TE/g)), and phenolic content (70.14 ± 0.53 mg GAE/100 g). Encapsulation is a sound technology to provide thermal stability and controlled release attributes to functional compounds such as plant seed oil. Nano-sized and micro-sized capsules harboring MSO were generated by utilizing thin film dispersion, spray drying, and lyophilization strategies. Fourier infrared transform analysis (FTIR), scanning electron microscopy (SEM), and particle size analyses were used for the authentication and morphological characterization of the samples. Spray drying and lyophilization effectuated the formation of microscale capsules (2660 ± 14 nm, 3140 ± 12 nm, respectively), while liposomal encapsulation brought about the development of nano-capsules (282.30 ± 2.35 nm). Nano-liposomal systems displayed significant thermal stability compared to microcapsules. According to in vitro release studies, microcapsules started to release MSO in simulated salivary fluid (SSF) and this continued in gastric (SGF) and intestinal (SIF) environments. There was no oil release for nano-liposomes in SSF, while limited release was observed in SGF and the highest release was observed in SIF. The results showed that nano-liposomal systems featured MSO thermal stability and controlled the release attributes in the gastrointestinal system (GIS) tract.

Eco-energy and environmental evaluation of cantaloupe production by life cycle assessment method

Environmental crises and resource depletion have adversely affected the food security around the world. Food security in the future can be guaranteed by sustainable agriculture that respects the environment. So, it is necessary to decrease the energy consumption of resources for agricultural productions to achieve the maximum sustainability. For agricultural productions, environmental and energy issues are completely interrelated, and a comprehensive evaluation is necessary to manage them in all productions. In this study, energy, environmental, and economic indicators in cantaloupe production were studied. The studied energy indices included energy efficiency, energy productivity, net energy gain, and energy intensity. Life cycle method based on ISO 14040 standard was used to evaluate the environmental impacts. This method includes goal statement, identification of inputs and outputs, and a system for assessing and interpreting the environmental impacts of various agricultural productions. Also, for economic analysis, the average prices of inputs and outputs and also net return (NR), gross return (GR), and profit-to-cost ratio were used. The results showed that nitrogen fertilizer (32.28%) and diesel fuel (30.52%) had the highest and cantaloupe seeds (0.39%), and oil consumption in tractor engines (0.43%) had the lowest share of energy consumption, respectively. Energy efficiency, energy productivity, energy intensity, and net energy gain were estimated 0.56, 0.70 kg MJ^-1, 1.41 MJ kg^-1, and - 11,775.86 MJ ha^-1, respectively. The results of the present status of environmental impacts showed that the most effective factor in climate change is direct emissions from the diesel fuel. Also, indirect emissions from phosphorus and urea fertilizers had the highest effect on ecosystem quality. Various machine operations such as primary and secondary plowing, spraying, and transportation were the main causes of high diesel fuel consumption. Economic analysis showed that the profit-to-cost ratio and the productivity values were calculated about 1.6 and 7.27, respectively, which means that for every dollar spent in cantaloupe farms, it produced 7.27 kg of cantaloupe production. The variable costs were estimated at 1154.5 and fixed cost was 1487 $ha^-1. Among the variable costs, transportation and fuel costs were the highest with 64.3%. Decreasing the diesel fuel consumption by using appropriate farm management methods and using the reduce tillage methods can play an effective role in reducing the consumption of this input and improving the energy, environmental, and economic indicators in cantaloupe production.

Integrated Mechanisms of Polarity-Based Extracts of Cucumis melo L. Seed Kernels for Airway Smooth Muscle Relaxation via Key Signaling Pathways Based on WGCNA, In Vivo, and In Vitro Analyses

The present study aimed to determine the mechanisms responsible for calcium-mediated smooth muscle contractions in C. melo seeds. The phytochemicals of C. melo were identified and quantified with the aid of Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC/ESI-MS/MS) and high-performance liquid chromatography (HPLC), and then tested in-vitro and in vivo to confirm involvement in smooth muscle relaxation. Allergic asthma gene datasets were acquired from the NCBI gene expression omnibus (GEO) and differentially expressed gene (DEG) analysis, weighted gene co-expression network analysis (WGCNA), and functional enrichment analysis were conducted. Additionally, molecular docking of key genes was carried out. Kaempferol, rutin, and quercetin are identified as phytochemical constituents of C. melo seeds. Results indicated that C. melo seeds exhibit a dose-dependent relaxant effect for potassium chloride (80 mM)- induced spastic contraction and calcium antagonistic response in calcium dose-response curves. The functional enrichment of WGCNA and DEG asthma-associated pathogenic genes showed cytokine-mediated pathways and inflammatory responses. Furthermore, CACNA1A, IL2RB, and NOS2 were identified as key genes with greater binding affinity with rutin, quercitrin, and kaempferol in molecular docking. These results show that the bronchodilator and antidiarrheal effects of C. melo were produced by altering the regulatory genes of calcium-mediated smooth muscle contraction.

Comparative analysis of pumpkin rootstocks mediated impact on melon sensory fruit quality through integration of non-targeted metabolomics and sensory evaluation

Melon fruits are popular because of sweet taste and pleasant aroma. Grafting has been extensively used for melons to alleviate abiotic stresses and control soil borne diseases. However, use of grafting for vegetable fruit quality improvement is less studies. In modern age fruit quality particularly sensory quality characteristics have key importance from consumer eye lens. We performed liquid chromatography-mass spectrometry and metabonomic analysis to examine sensory fruit quality of melon grafted onto ten different pumpkin rootstocks. Bases on the result of our study, 478 metabolites were detected and 184 metabolites consisting of lipids, amino acids and organic oxygen compounds were differentially expressed in grafted melon fruits. The results from metabolomic, physiochemical and sensory analysis explain the differences in melon fruit flavor from two contrasting rootstocks. In conclusion the fruits from Tianzhen No. 1 rootstock exhibited better organoleptic characteristics and higher soluble sugars content [glucose (19.87 mg/g), fructose (19.68 mg/g) and sucrose (169.45 mg/g)] compared with other rootstocks used in this study. Moreover, the contents of bitterness causing amino acids such as L-arginine, L-asparagine, Histidinyl-histidine and Acetyl-DL-valine were found lower in Tianzhen No. 1-grafted melon fruits compared with Sizhuang No. 12-grafted melon fruits. These fruit quality characteristics made Tianzhen No. 1 rootstock suitable for commercial cultivation of Yuniang melon.

Selected Species of the Cucurbitaceae Family Used in Mexico for the Treatment of Diabetes Mellitus

In Mexico, Diabetes mellitus (DM) is a serious health problem, and although the current pharmacological treatments for DM such as insulin and oral hypoglycemics are available, the Mexican population continues to use medicinal plants in the treatment of DM. The antidiabetic properties of the plant species that belong to the Cucurbitaceae family has already been recognized worldwide. Since Mexico is one of the most important centers of diversity of Cucurbitaceae, the present work contributes to the review of the most used species of Cucurbitaceae in the treatment of DM in Mexico. The reviewed species (Cucurbita ficifolia, C. maxima, C. moschata, C. pepo, Ibervillea sonorae, Sechium edule, Citrullus lanatus, Cucumis melo, and C. sativus) revealed that the antidiabetic effects exerted are effective in a number of mechanisms involved in the complex pathogenesis of DM: hypoglycemic, antioxidant, anti-inflammatory, anti-obesity, protective effects on diverse organs and cells, as well as in the control of dyslipidemias; furthermore, the select species of the Cucurbitaceae family could also be essential components of diets for the control of DM in patients with the disease. Thus, the Cucurbitaceae species selected in the present work represent a source of antidiabetic agents that perhaps establish the bases for novel clinical treatments.

Valorisation of food agro-industrial by-products: From the past to the present and perspectives

Food agro-industrial by-products mainly include peels, seeds, stems, bagasse, kernels, and husk, derived during food processing. Due to their overproduction and the lack of sustainable management, such by-products have been conventionally rejected and wasted in landfills, being the principal strategy for their treatment, but nowadays, this strategy has been associated with several environmental, social and economic issues. Hence, we focused on the use of different consolidated biotechnological processes and methodologies as suitable strategies for food by-products management and valorisation, highlighting them as potential bioresources because they still gather high compositional and nutritional value, owing to their richness in functional and bioactive molecules with human health benefits. Food by-products could be utilised for the development of new food ingredients or products for human consumption, promoting their integral valorisation and reincorporation to the food supply chain within the circular bioeconomy concept, creating revenue streams, business and job opportunities. In this review, the main goal was to provide a general overview of the food agro-industrial by-products utilised throughout the years, improving global sustainability and human nutrition, emphasising the importance of biowaste valorisation as well as the methodologies employed for the recovery of value-added molecules.

Fruit Wastes as a Valuable Source of Value-Added Compounds: A Collaborative Perspective

The by-products/wastes from agro-food and in particular the fruit industry represents from one side an issue since they cannot be disposed as such for their impact on the environment but they need to be treated as a waste. However, on the other side, they are a source of bioactive healthy useful compounds which can be recovered and be the starting material for other products in the view of sustainability and a circular economy addressing the global goal of "zero waste" in the environment. An updated view of the state of art of the research on fruit wastes is here given under this perspective. The topic is defined as follows: (i) literature quantitative analysis of fruit waste/by-products, with particular regards to linkage with health; (ii) an updated view of conventional and innovative extraction procedures; (iii) high-value added compounds obtained from fruit waste and associated biological properties; (iv) fruit wastes presence and relevance in updated databases. Nowadays, the investigation of the main components and related bioactivities of fruit wastes is being continuously explored throughout integrated and multidisciplinary approaches towards the exploitation of emerging fields of application which may allow to create economic, environmental, and social value in the design of an eco-friendly approach of the fruit wastes.

Enhancement of a Landrace of Carosello (Unripe Melon) through the Use of Light-Emitting Diodes (LED) and Nutritional Characterization of the Fruit Placenta

Landraces of ‘Carosello’ (Cucumis melo L.) are a typical expression of Apulia’s agro-biodiversity and are consumed in the same way as cucumbers. The aim of this research was to valorize the cultivation of a local variety of ‘Carosello’, extending the cultivation period and valorizing a part of the fruits that are generally wasted (endosperm). To accomplish this, a local variety called ‘Carosello leccese’ was grown in a greenhouse during the fall season under red + blue and red + blue + far red light-emitting diodes (LED) interlight. Yield, morphology, color and biochemical composition of the external and internal part of the fruit were evaluated. Although yield increased by 26% under supplemental light, the fruit quality was not influenced by LED application. However, the exocarp was greener (chlorophylls) and more yellow (carotenoids) than the mesocarp. Finally, the endosperm, which is the part of the fruit that is generally wasted, showed the highest polyphenols content, proving to be an important source of nutraceutical compounds. Therefore, it was demonstrated that the nutritional value of the endosperm is comparable or higher than the external part of the fruit, but further studies will be necessary to valorize it from a culinary perspective.

Nutritional Composition and Health Benefits of Various Botanical Types of Melon (Cucumis melo L.)

Characterizing the diverse melon cultivars for nutrition aids in crop improvement and promoting a healthy diet. Here, we used in vitro assays to characterize the nutritional qualities and health-beneficial effects of 30 melon (Cucumis melo L.) genotypes, including 10 improved cultivars, 16 landraces, and 4 wild types collected from different parts of India. Two landraces (Sidoota and Alper Green) had the highest (12.20 and 11.25) total soluble solids (TSS) contents. The Sidoota and Pappusa landraces had high reducing sugar contents (2.84 and 2.81 mg g⁻¹ fresh weight [FW]). The highest polyphenols contents (22.0 mg g⁻¹ FW) were observed in the landraces Mage Kaayi-2, Budamekaayi, and Small Melon. Reflecting on the primary and secondary metabolite contents, the Mekke Kaayi and Giriyala landraces exhibited high 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (97.6 and 91% at 100 μg mL⁻¹). Additionally, seven of the landraces showed significant nitric oxide (NO) induction activity (>80% inhibition at 200 μg mL⁻¹), indicating their potential health benefits, and seven showed considerable angiotensin-converting enzyme (ACE) inhibition activity (highest in Kashi Madhu), indicating their potential usefulness in reducing hypertension. Genotypes with high health beneficial compounds identified in this study can be used for breeding improved melon cultivars to promote these fruits as well as a healthy diet.

Impact of Diets Including Agro-Industrial By-Products on the Fatty Acid and Sterol Profiles of Larvae Biomass from Ephestia kuehniella, Tenebrio molitor and Hermetia illucens

Simple Summary

Insects are a promising source of lipids. Their fatty acid compositions can vary as a function of diet composition, rearing conditions and developmental stage. In the present study, different agro-industrial by-products were used to feed the insects. Then, the fatty acids and sterols were determined. Notably, these profiles were assessed for the first time for E. kuehniella. According to our results, fatty acid profiles showed differences depending on diet composition, but mostly depended on species. Sterols varied significantly as a function of diet composition and species, showing low cholesterol and high campesterol and β-sitosterol levels in H. illucens, and high cholesterol and low campesterol contents in T. molitor and E. kuehniella. These results suggest that insects are an interesting alternative source of fat for humans and animals, which might promote the use of insects for circular economy practices.

Abstract

Rearing insects on agro-industrial by-products is a sustainable strategy for the circular economy while producing valuable products for feed and foods. In this context, this study investigated the impact of larvae diet containing agro-industrial by-products on the contents of fatty acids and sterols of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), Tenebrio molitor (L.) (Coleoptera: Tenebrionidae), and Hermetia illucens (L.) (Diptera: Stratiomyidae). For each insect, selected diets were formulated using single or combined agro-industrial by-products (i.e., apricot, brewer’s spent grain and yeast, and feed mill) and compared to a control diet. Fatty acid profiles showed differences depending on diet composition, but mostly depended on species: H. illucens was characterized by the abundance of C12:0, C16:0 and C18:2, whereas C:16, C18:1(n-9c), and C18:2(n-6c) were predominant in T. molitor and E. kuehniella. Sterols significantly varied as a function of diet composition and species. H. illucens showed low cholesterol levels and high campesterol and β sitosterol levels (0.031, 0.554 and 1.035 mg/g, respectively), whereas T. molitor and E. kuehniella had high cholesterol and low campesterol contents (1.037 and 0.078 g/kg, respectively, for T. molitor; 0.873 and 0.132 g/kg, respectively, for E. kuehniella).

Effect of Dietary Sugarcane Bagasse Supplementation on Growth Performance, Immune Response, and Immune and Antioxidant-Related Gene Expressions of Nile Tilapia (Oreochromis niloticus) Cultured under Biofloc System

Simple Summary

Supplementation of agriculture by-product as functional feed additives in combination with biofloc technology (a sustainable and environmentally friendly technology) has recently gained much attention in aquaculture. In the present study, sugarcane bagasse powder can possibly be applied as a feed additive to improve growth performance, immune response, and immune and antioxidant-related gene expression.

Abstract

We investigated, herein, the effects of dietary inclusion of sugarcane bagasse powder (SB) on Nile tilapia development, mucosal and serum immunities, and relative immune and antioxidant genes. Fish (15.12 ± 0.04 g) were provided a basal diet (SB0) or basal diet incorporated with SB at 10 (SB10), 20 (SB20), 40 (SB40), or 80 (SB80) g kg⁻¹ for 8 weeks. Our results demonstrated that the dietary incorporation of sugarcane bagasse powder (SB) at 20 and 40 g kg⁻¹ significantly ameliorated FW, WG, and SGR as opposed to fish fed basal, SB10, and SB80 diets. However, no significant changes in FCR and survivability were observed between the SB supplemented diets and the control (basal diet). The mucosal immunity exhibited significantly higher SMLA and SMPA activities (p < 0.005) in fish treated with SB diets after eight weeks. The highest SMLA and SMPA levels were recorded in fish fed SB80 followed by SB20, SB40, and SB10, respectively. For serum immunity, fish fed SB incorporated diets significantly ameliorated SL and RB levels (p < 0.05) compared with the control. However, SP was not affected by the inclusion of SB in any diet throughout the experiment. The expression of IL1, IL8, LBP, GSTa, GPX, and GSR genes in the fish liver was significantly increased in fish fed the SB20 and SB10 diets relative to the basal diet fed fish (p < 0.05); whereas only the IL8, LBP, and GPX genes in the intestines were substantially augmented via the SB20 and SB80 diets (p < 0.05). IL1 and GSR were not influenced by the SB incorporated diets (p > 0.05). In summary, sugarcane bagasse powder (SB) may be applied as a feed additive to improve growth performance, immune response, and immune and antioxidant-related gene expression in Nile tilapia.

Milk yield and composition, feed efficiency, haemato-biochemical parameters and antioxidant status of lactating ewes fed diet supplemented with prickly pear cactus peels

Prickly pear cactus peels (Opuntia ficus-indica, PPCP) are a powerful source of antioxidant components and available as a by-product in arid regions in large quantities. The current work investigated the effect of dietary supplementation of PPCP on feed efficiency, milk yield and composition, haematology, serum biochemical constituents and antioxidant status of lactating Barki ewes. Fifteen multiparous female Barki sheep (2-3 years old, body weight post partum 46.9 ± 0.59 kg) were individually and randomly distributed into three groups (five ewes each). The first group was the control without PPCP supplementation; the second and third groups were fed for 60 d diets supplemented with dried PPCP powder at daily doses of 5 and 10 g/ewe, respectively. The results revealed a significant increase in total dry matter intake (p ≤ 0.001) and numerical rise in total milk yield (p = 0.054) with PPCP addition at 5 g/ewe compared with the control group. The serum lipid profile was significantly altered by PPCP supplementation. Serum urea nitrogen decreased (p ≤ 0.001) with PPCP treatment. Antioxidant enzyme activities, such as superoxide dismutase, catalase and glutathione peroxidase, were significantly increased (p ≤ 0.001) and the level of thiobarbituric acid-reactive substances was significantly decreased (p ≤ 0.001) with increasing PPCP supplementation levels in a dose-dependent manner. In conclusion, supplementation with 5 g PPCP improved total dry matter intake, serum lipid profiles and antioxidant status in Barki ewes during lactation.

Valorisation of Olea europaea L. Olive Leaves through the Evaluation of Their Extracts: Antioxidant and Antimicrobial Activity

Olea europaea L. leaves constitute a source of bioactive compounds with recognized benefits for both human health and technological purposes. In the present work, different extracts from olive leaves were obtained by the application of two extraction methods, Soxhlet and microwave-assisted extraction (MAE), and six solvents (distilled water, ethanolic and glycerol mixtures solvents). MAE was applied under 40, 60 and 80 °C for 3, 6.5 and 10 min. The effect of the extraction method, solvent and treatment factors (the latter in MAE) on the total phenol content (TPC), the antioxidant activity (AA) and the phenolic profile of the extracts were all evaluated. The extracts showed high values of TPC (up to 76.1 mg GAE/g DW) and AA (up to 78 mg TE/g DW), with oleuropein being the most predominant compound in all extracts. The Soxhlet extraction method exhibited better yields in TPC than in MAE, although both methods presented comparable AA values. The water MAE extract presented the strongest antimicrobial activity against five foodborne pathogens, with minimum inhibitory concentration (MIC) values ranging from 2.5 to 60 mg/mL. MAE water extract is proposed to be exploited in the food and nutraceutical industry in the frame of a sustainable economy.

Plant Secondary Metabolites: An Opportunity for Circular Economy

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement "greener" practices in the latter sector.

Environmentally Friendly Hydrothermal Processing of Melon by-Products for the Recovery of Bioactive Pectic-Oligosaccharides

Melon by-products, that currently lack high value-added applications, could be a sustainable source of bioactive compounds such as polysaccharides and antioxidants. In this work, melon peels were extracted with water to remove free sugars, and the water-insoluble solids (WISs) were subjected to hydrothermal processing. The effect of temperature on the composition of the obtained liquors and their total phenolic content was evaluated. The selected liquors were also characterized by matrix assisted laser desorption/ionization-time of flight mass spectroscopy (MALDI-TOF MS), fourier transform infrared spectroscopy (FTIR) and high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and its phenolic compounds were identified and quantified by high-performance liquid chromatography-diode array detector-tandem mass spectrometry (HPLC-DAD-MS/MS). In addition, the spent solids from the hydrothermal treatment were characterized and their potential use was assessed. At the optimal conditions of 140 °C (severity 2.03), the total oligosaccharide yield accounted for 15.24 g/100 g WIS, of which 10.07 g/100 g WIS were oligogalacturonides. The structural characterization confirmed the presence of partially methyl esterified oligogalacturonides with a wide range of polymerization degrees. After precipitation, 16.59 g/100 g WIS of pectin were recovered, with a galacturonic acid content of 55.41% and high linearity.

Effect of Prickly Pear Cactus Peel Supplementation on Milk Production, Nutrient Digestibility and Rumen Fermentation of Sheep and the Maternal Effects on Growth and Physiological Performance of Suckling Offspring

Simple Summary

The agricultural byproducts commonly used as a feedstuff depend on their high abundance and the nutritional composition. Moreover, several agricultural byproducts are a valuable source of active ingredients, which could be used as feed supplements to improve the quality of formulated diets and animal performance. The present study evaluated the use of prickly pear cactus peels (Opuntia ficus-indica, PPCP) as an agricultural byproduct rich with phytochemicals in the diet of lactating Barki ewes at two doses (5 and 10 g/head/day). Supplementation with 5 g PPCP improves the milk production and composition of ewes. The maternal effect of supplementation of both doses of PPCP in the diets of lactating Barki ewes has been successful to improve the serum lipid profile, kidney function, hormonal and antioxidant status of their suckling lambs. Moreover, supplementation with 5 g PPCP improves the nutrient digestibility and rumen fermentation parameters in the sheep.

Abstract

Prickly pear cactus peels (Opuntia ficus-indica, PPCP) are sustainable byproducts available in arid regions and a rich source of antioxidants. Fifteen multiparous Barki ewes (2–3 years old, 46.94 ± 0.59 kg body weight, BW) at postpartum were individually distributed in three equal groups and fed diets supplemented with PPCP at doses of 0, 5 and 10 g/head/day. Lambs were individually distributed into three equal groups according to their mothers’ groups to investigate the maternal effect on lambs’ growth performance, hematology and serum metabolites. This trial lasted for 56 days from birth to weaning. Moreover, nine adult male Barki sheep with a live BW of 65.76 ± 0.54 kg were randomly allocated into three equal groups to determine the effect of PPCP on the nutrient digestibility of the experimental diets. The results indicate that supplementing PPCP at low levels (5 g/head/day) increased milk yield (p = 0.050), fat-corrected milk (p = 0.022), energy-corrected milk (p = 0.015) and the yield of milk constituents compared to 10 g PPCP and the control group. In addition, lambs suckling from ewes fed the diet supplemented with 5 g PPCP had a higher (p = 0.001) weaning BW compared to other groups. Serum total protein, globulin, superoxide dismutase, glutathione peroxidase enzyme activities and the triiodothyronine hormone improved significantly in lambs suckling from ewes fed diets supplemented with 5 g PPCP compared to the control group. Serum cholesterol profile and kidney activities were enhanced significantly in lambs suckling from ewes fed diets supplemented with 5 and 10 g of PPCP compared to the control group. The dietary supplementation of 5 g PPCP improved the crude protein digestibility, digestible crude protein value, nitrogen balance and rumen fermentation characteristics of male sheep compared to the control group. In conclusion, supplementation with 5 g PPCP improved ewes’ milk production, offspring growth and physiological status. Furthermore, it improved the crude protein digestibility and rumen fermentation characteristics of Barki sheep.

A chemical valorisation of melon peels towards functional food ingredients: Bioactives profile and antioxidant properties

The goal of this work was to characterize the profile of bioactive compounds and the antioxidant activity of inodorus melon peels. Melon peels were divided into three fractions: a solid fraction with a higher content of carbohydrates (84.81%); a liquid fraction with a higher ash content (11.5%); and a pellet fraction with a higher protein content (34.90%). The structural carbohydrates study revealed a composition of cellulose (27.68%), hemicellulose (8.2%) and lignin (26.46%) in the solid fraction. The liquid fraction had the highest antioxidant activity based on results from DPPH, ABTS and ORAC assays. Flavones, hydroxybenzoic and hydroxycinnamic acids were the main phenolic classes found in all fractions. In addition, β-carotene, lutein, β-cryptoxanthin and violaxanthin had also been quantified. Melon fractions were rich in nutrients and bioactive substances and could be useful in the development of novel functional products, considering the growing market demand for safe and healthy food products.

Polyphenol Extraction by Different Techniques for Valorisation of Non-Compliant Portuguese Sweet Cherries towards a Novel Antioxidant Extract

Currently, there is special interest in the recovery of polyphenols from non-compliant fruits that have no market value; efforts to find value-added solutions for these food areas are a key option for a sustainable bio-economy. Saco cherries are a traditional Portuguese cherry variety, and although they are a nutritionally important food, rich in powerful dietary polyphenols, significant amounts of these cherries are not sold due to their small size. In this context, this work aimed to select the best method to produce novel antioxidant polyphenol-rich extracts from low calibre and non-compliant Saco cherries. Based on the results, microwaves-assisted extraction (MAE) allowed us to obtain a polyphenol-rich extract with a high antioxidant capacity (50.46 ± 1.58 mg Trolox equivalent (TE)/g dry extract (DE) by oxygen radical absorbance capacity (ORAC), 10.88 ± 0.38 mg ascorbic acid equivalent (AA)/g DE by 2-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and 9.58 ± 0.42 mg TE/g DE by 2,2-diphenyl-1-picrylhydrazyl (DPPH)) and a high content of polyphenols, namely, hydroxycinnamic acids (neochlorogenic and p-coumaric acids) and anthocyanins (cyanidin-3-rutinoside and cyanidin-3-glucoside), compared with those of conventional extractions with low and high temperature and ultrasound-assisted extraction. The antioxidant extract produced from MAE could be a new alternative for the valorisation of non-compliant cherries since these extracts proved to be a functional ingredient due to the high content of antioxidants, which are linked to the prevention of diseases.