Evaluation and optimization of microwave‐assisted extraction of bioactive compounds from eggplant peel by‐product

Ultrasound-Assisted Extraction of Bioactive Compounds from Broccoli By-Products

The objective of this work was to gain insight into the operating conditions that affect the efficiency of ultrasound-assisted extraction (UAE) parameters to achieve the best recovery of bioactive compounds from broccoli leaf and floret byproducts. Therefore, total phenolic content (TPC) and the main sulfur bioactive compounds (sulforaphane (SFN) and glucosinolates (GLSs)) were assayed. Distilled water was used as solvent. For each byproduct type, solid/liquid ratio (1:25 and 2:25 g/mL), temperature (25, 40, and 55 °C), and extraction time (2.5, 5, 7.5, 10, 15, and 20 min) were the studied variables to optimize the UAE process by using a kinetic and a cubic regression model. TPC was 12.5-fold higher in broccoli leaves than in florets, while SFN was from 2.5- to 4.5-fold higher in florets regarding the leaf's extracts obtained from the same plants, their precursors (GLS) being in similar amounts for both plant tissues. The most efficient extraction conditions were at 25 °C, ratio 2:25, and during 15 or 20 min according to the target phytochemical to extract. In conclusion, the type of plant tissue and used ratio significantly influenced the extraction of bioactive compounds, the most efficient UAE parameters being those with lower energy consumption.

Valorization of pineapple rind for bromelain extraction using microwave assisted technique: optimization, purification, and structural characterization

Huge amount of waste is generated by the pineapple processing industries which raises concerns regarding its safe disposal into the environment. This ever-increasing problem of waste management can be solved by the valorization of pineapple by-products to high-value compounds. The extraction of proteolytic enzyme, bromelain from pineapple rind using green techniques can help to overcome the drawbacks associated with conventional methods. In the present study, the extraction of bromelain from pineapple rind using microwave assisted technique resulted in considerable amount of proteolytic activity (127.8 U/mL) and protein content (2.55 mg/mL). The optimized extraction conditions were found as 200 W microwave power, 1:5 solid/ liquid ratio and after treatment time of 10 min. Highest specific activity (512 U/mg) of bromelain was obtained after using gel filtration chromatography. FTIR result confirmed the presence of functional groups in bromelain, whereas, XRD analysis indicated the semi-crystalline nature of bromelain. The results indicated MAE as an effective green technique for the extraction of bromelain from pineapple rind. The proteolytic action of the extracted bromelain makes it a suitable functional ingredient for its applications in bakery, dairy, and seafood processing industries.

The way forward to produce nutraceuticals from agri-food processing residues: obstacle, solution, and possibility

Food matrices contain bioactive compounds that have health benefits beyond nutritional value. The bulk of bioactive chemicals are still present in agro-industrial by-products as food matrices. Throughout the food production chain, there is a lot of agro-industrial waste that, if not managed effectively, could harm the environment, company, and how nutritiously and adequately people eat. It's important to establish processes that maximise the use of agro-industrial by-products, such as biological technologies that improve the extraction and acquisition of bioactive compounds for the food and pharmaceutical industries. As opposed to nonbiological processes, biological procedures provide high-quality, bioactive extracts with minimum toxicity and environmental impact. Fermentation and enzymatic treatment are biological processes for obtaining bioactive compounds from agro-industrial waste. In this context, this article summarises the principal bioactive components in agro-industrial byproducts and the biological methods employed to extract them. In this review efficient utilization of bioactive compounds from agro-industrial waste more effectively in food and pharmaceutical industries has been described.

Optimization of aqueous extraction of antioxidants from Chrysanthemum (C. morifolium Ramat and C. indicum L.) flowers and evaluation of their protection from glycoxidation damage on human αA-crystallin

Chrysanthemum tea is commonly consumed by Chinese consumers mainly due to the Chrysanthemum flower being a potential source of antioxidants. The current study investigates the effects of extraction time and temperature on Chrysanthemum flower aqueous extract (CFAE) antioxidant capacity, including Trolox equivalent antioxidant capacity (TEAC), ferrous iron-chelating activity, and superoxide radical scavenging capacity (SRSC) using a two-factor, three-level factorial design of the response surface method (RSM). The TEAC and SRSC of CFAE are higher at higher temperatures and longer times up to a certain point, and the highest TEAC and SRSC are achieved at a 100 °C extraction temperature for 45 min. The fructose induced-αA-crystallin (Cry) glycation model system was used to evaluate the effects of the CFAE on anti-glycoxidation activities. The antioxidant ingredients obtained from CFAE significantly impede the production of advanced glycation end products from protein glycoxidation products (dityrosine, kynurenine, and N'-methylkynurenine) in the glycation process of αA-Cry and exhibit strong anti-glycating activity. The glycation inhibitory effects of CFAE are concentration-dependent. C. indicum L. exhibits greater potential for preventing cataracts compared to C. morifolium Ramat CFAE's antioxidant and anti-glycation properties suggest its potential application as a natural ingredient in the development of agents to combat glycation.

A Review on the Potential Bioactive Components in Fruits and Vegetable Wastes as Value-Added Products in the Food Industry

The food production industry is a significant contributor to the generation of millions of tonnes of waste every day. With the increasing public concern about waste production, utilizing the waste generated from popular fruits and vegetables, which are rich in high-added-value compounds, has become a focal point. By efficiently utilizing food waste, such as waste from the fruit and vegetable industries, we can adopt a sustainable consumption and production pattern that aligns with the Sustainable Development Goals (SDGs). This paper provides an overview of the high-added-value compounds derived from fruit and vegetable waste and their sources. The inclusion of bioactive compounds with antioxidant, antimicrobial, and antibrowning properties can enhance the quality of materials due to the high phenolic content present in them. Waste materials such as peels, seeds, kernels, and pomace are also actively employed as adsorbents, natural colorants, indicators, and enzymes in the food industry. Therefore, this article compiles all consumer-applicable uses of fruit and vegetable waste into a single document.

Current Challenges in the Sustainable Valorisation of Agri-Food Wastes: A Review

In the upcoming years, the world will face societal challenges arising, in particular, from the impact of climate change and the inefficient use of natural resources, in addition to an exponential growth of the world population, which according to the United Nations (UN) estimations will be 9.8 billion in 2050. This increasing trend requires optimized management of natural resources with the use of value-added waste and a significant reduction in food loss and food waste. Moreover, the recent pandemic situation, COVID-19, has contributed indisputably. Along with the agri-food supply chain, several amounts of waste or by-products are generated. In most cases, these biomass wastes cause serious environmental concerns and high costs to enterprises. The valorisation of the agri-food loss and food industry wastes emerged as a useful strategy to produce certain value-added compounds with several potential applications, namely in the food, health, pharmaceutical, cosmetic, and environmental fields. Therefore, in this review, some of the crucial sustainable challenges with impacts on the valorisation of agri-food loss/wastes and by-products are discussed and identified, in addition to several opportunities, trends and innovations. Potential applications and usages of the most important compounds found in food loss/waste will be highlighted, with a focus on the food industry, pharmaceutical industry, and the environment.

The Greening of Anthocyanins: Eco-Friendly Techniques for Their Recovery from Agri-Food By-Products

In recent years, several steps forward have been made toward a more sustainable approach for the extraction of bioactive compounds from plant materials based on the application of green extraction principles. It is currently recognized that waste and by-products deriving from agriculture and food industries still contain a wide array of high value-added substances, which can be re-used to obtain new products with various applications in the food, supplement, pharmaceutical, and cosmetic industries. Anthocyanins are a class of these valuable metabolites; they confer the red, violet, and blue color to fruits and vegetables, and scientific evidence has accumulated over the last few decades to support their beneficial effects on human health, in great part deriving from their powerful antioxidant capacity. This review provides a general overview of the most recent green procedures that have been applied for the recovery of anthocyanins from plant-derived wastes and by-products. The most widely used green solvents and the main sustainable techniques utilized for recovering this class of flavonoids from various matrices are discussed, together with the variables that mainly impact the extraction yield.

Extraction and Characterization of Antioxidant Compounds in Almond (Prunus amygdalus) Shell Residues for Food Packaging Applications

This work proposes the revalorization of almond shell (AS) wastes as an active additive for food packaging applications. A new microwave-assisted extraction (MAE) method to obtain extracts rich in polyphenolic compounds with high antioxidant capacity was optimized. An experimental design to optimize the MAE procedure through response surface methodology (RSM) using a Box-Behnken design was proposed. The effects of extraction temperature, irradiation time, ethanol:water concentration, and solvent pH at three levels were evaluated in terms of total phenolic content (TPC) and antioxidant activity (DPPH (2,2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) assays). The optimal conditions found were 57 min, 80 °C, pH 8, and 70% (v/v) ethanol. Optimized MAE extracts showed low soluble protein content (0.43 mg BSA g^-1) and were rich in TPC (5.64 mg GAE g^-1), flavonoids (1.42 mg CE g^-1), and polysaccharides (1.59 mg glucose g^-1), with good antioxidant capacity (2.82 mg AAE acid g^-1). These results suggest the potential application of these extracts in the food industry as active additives. This strategy opens new pathways to valorize almond shell residues, contributing to the circular economy.

Valorization of Food Processing Waste to Produce Valuable Polyphenolics

Traditional incineration and landfill of food processing waste (FPW) have polluted the environment and underutilized valuable bioactive compounds, including polyphenols in food waste. As one of the most widely occurring compounds in the FPW, polyphenols possess high utilization value in many fields such as human health, energy, and environmental protection. Extracting polyphenols directly from FPW can maximize the value of polyphenols and avoid waste of resources. However, traditional polyphenol extraction methods mostly use the Soxhlet extraction, infiltration, and impregnation method, consuming a large amount of organic solvent and suffering from long extraction time and low extraction efficiency. Emerging green extraction methods such as supercritical fluid extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and other methods can shorten the extraction time and improve the solvent extraction efficacy, resulting in the green and safe recovery of polyphenols from FPW. In this paper, the traditional treatment methods of FPW waste and the application of polyphenols in FPW are briefly reviewed, and the traditional extraction methods and emerging green extraction methods of polyphenols in FPW are compared to obtain insight into the start-of-the-art extraction approaches.

Effect of Microwave-Assisted Aqueous Two-Phase Extraction of α-Solanine from S. retroflexum and Analysis on UHPLC-qTOF-MS

A new, fast and efficient method, hyphenated microwave-assisted aqueous two-phase extraction (MA-ATPE) was applied in the extraction of α-solanine from Solanum retroflexum. This environmentally friendly extraction method applied water and ethanol as extraction solvents. Central composite design (CCD) was performed which included numerical parameters such as time, mass of plant powder and microwave power. The categorical factors included the chaotrope — NaCl or the kosmotrope — Na2CO3. Fitting the central composite design response surface model to the data generated a quadratic model with a good fit (R2 = 0.920). The statistically significant (p < 0.05) parameters such as time and mass of plant powder were influential in the extraction of α-solanine. Quantification of α-solanine was achieved using a robust and sensitive feature of the ultra-high performance quadrupole time of flight mass spectrometer (UHPLC-qTOF-MS), multiple reaction monitoring (MRM). The optimized condition for the extraction of α-solanine in the presence of NaCl and Na2CO3 was a period of 1 min at a mass of 1.2 g using a microwave power of 40%. Maximal extraction of α-solanine was 93.50 mg kg−1 and 72.16 mg kg−1 for Na2CO3 and NaCl, respectively. The synergistic effect of salting-out and microwave extraction was influential in extraction of α-solanine. Furthermore, the higher negative charge density of the kosmotrope (Na2CO3) was responsible for its greater extraction of α-solanine than chaotrope (NaCl). The shorter optimal extraction times of MA-ATPE make it a potential technique that could meet market demand as it is a quick, green and efficient method for removal of toxic metabolites in nutraceuticals.

Optimization of Microwave-Assisted Extraction of Polyphenols from Lemon Myrtle: Comparison of Modern and Conventional Extraction Techniques Based on Bioactivity and Total Polyphenols in Dry Extracts

The aromatic herb lemon myrtle is a good source of polyphenols, with high antioxidant and antimicrobial capacity. In this study, the green extraction technique microwave-assisted extraction (MAE) was applied and the extraction parameters were optimized using response surface methodology (RSM) to maximize the extraction yield of phenolic compound and antioxidant properties. Then, it was compared with other popular novel and conventional extraction techniques including ultrasound-assisted extraction (UAE) and shaking water bath (SWB) to identify the most effective technique for extraction of phenolic compounds from lemon myrtle. The results showed that the MAE parameters including radiation time, power, and sample to solvent ratio had a significant influence on the extraction yield of phenolic compounds and antioxidant capacity. The optimal MAE conditions were radiation time of 6 min, microwave power of 630 W, and sample to solvent ratio of 6 g/100 mL. Under optimal conditions, MAE dry extract had similar levels of total phenolic compounds (406.67 ± 8.57 mg GAE/g DW), flavonoids (384.57 ± 2.74 mg CE/g DW), proanthocyanidins (336.54 ± 7.09 mg CE/g DW), antioxidant properties, and antibacterial properties against (Staphylococcus lugdunensis and Bacillus cereus) with the other two methods. However, MAE is eight-times quicker and requires six-times less solvent volume as compared to UAE and SWB. Therefore, MAE is recommended for the extraction of polyphenols from lemon myrtle leaf.

Bio Discarded from Waste to Resource

The modern linear agricultural production system allows the production of large quantities of food for an ever-growing population. However, it leads to large quantities of agricultural waste either being disposed of or treated for the purpose of reintroduction into the production chain with a new use. Various approaches in food waste management were explored to achieve social benefits and applications. The extraction of natural bioactive molecules (such as fibers and antioxidants) through innovative technologies represents a means of obtaining value-added products and an excellent measure to reduce the environmental impact. Cosmetic, pharmaceutical, and nutraceutical industries can use natural bioactive molecules as supplements and the food industry as feed and food additives. The bioactivities of phytochemicals contained in biowaste, their potential economic impact, and analytical procedures that allow their recovery are summarized in this study. Our results showed that although the recovery of bioactive molecules represents a sustainable means of achieving both waste reduction and resource utilization, further research is needed to optimize the valuable process for industrial-scale recovery.

Anthocyanins Recovered from Agri-Food By-Products Using Innovative Processes: Trends, Challenges, and Perspectives for Their Application in Food Systems

Anthocyanins are naturally occurring phytochemicals that have attracted growing interest from consumers and the food industry due to their multiple biological properties and technological applications. Nevertheless, conventional extraction techniques based on thermal technologies can compromise both the recovery and stability of anthocyanins, reducing their global yield and/or limiting their application in food systems. The current review provides an overview of the main innovative processes (e.g., pulsed electric field, microwave, and ultrasound) used to recover anthocyanins from agri-food waste/by-products and the mechanisms involved in anthocyanin extraction and their impacts on the stability of these compounds. Moreover, trends and perspectives of anthocyanins' applications in food systems, such as antioxidants, natural colorants, preservatives, and active and smart packaging components, are addressed. Challenges behind anthocyanin implementation in food systems are displayed and potential solutions to overcome these drawbacks are proposed.