Effect of ultrasound, high-pressure processing, and enzymatic hydrolysis on carbohydrate hydrolyzing enzymes and antioxidant activity of lemon (Citrus limon) flavedo

Investigating the impact of storage duration and temperature on vitamin C in various citrus genotypes: A meta-analysis method

The present work disseminates a solid scientific meta-analysis method to investigate the impact of storage duration and temperature on vitamin C of citrus. This work is initiated by designing of the PICO framework, collecting, and organizing the articles, creating selection criteria, sorting articles, identifying factors influencing moderation effects and sources of diversity, tabulating data, and employing analysis in the form of a linear mixed model. Using this method, we identified 54 distinct studies from a pool of 289 eligible peer-reviewed publications, focusing on variations of vitamin C in citrus. The method provides mean values in both quadratic and linear regression forms.•This method provides a detailed description starting from topic selection to statistical methodologies intended for performing meta-analysis.•All guidelines for conducting this method have been approved by all authors and adhere to the standard PRISMA-P guidelines.•Disseminating this method in a peer-reviewed publication aims to facilitate scholarly discussions and promote transparency, ultimately improving the standard for performing meta-analysis on vitamin C levels in citrus concerning various genotypes, storage temperatures, and durations.

Comparative Study of Microwave, Pulsed Electric Fields, and High Pressure Processing on the Extraction of Antioxidants from Olive Pomace

Olive oil production is characterized by large amounts of waste, and yet is considerably highly valued. Olive pomace can serve as a cheap source of bioactive compounds (BACs) with important antioxidant activity. Novel technologies like Pulsed Electric Fields (PEF) and High Pressure (HP) and microwave (MW) processing are considered green alternatives for the recovery of BACs. Different microwave (150-600 W), PEF (1-5 kV/cm field strength, 100-1500 pulses/15 µs width), and HP (250-650 MPa) conditions, in various product/solvent ratios, methanol concentrations, extraction temperatures, and processing times were investigated. Results indicated that the optimal MW extraction conditions were 300 W at 50 °C for 5 min using 60% v/v methanol with a product/solvent ratio of 1:10 g/mL. Similarly, the mix of 40% v/v methanol with olive pomace, treated at 650 MPa for the time needed for pressure build-up (1 min) were considered as optimal extraction conditions in the case of HP, while for PEF the optimal conditions were 60% v/v methanol with a product/solvent ratio of 1:10 g/mL, treated at 5000 pulses, followed by 1 h extraction under stirring conditions. Therefore, these alternative extraction technologies could assist the conventional practice in minimizing waste production and simultaneously align with the requirements of the circular bioeconomy concept.

Vitamin C variation in citrus in response to genotypes, storage temperatures, and storage times: A systematic review and meta-analysis

Numerous published studies have highlighted discrepancies in the duration and storage temperature used for preserving vitamin C content on various citrus genotypes worldwide. The present study aimed to analyze the variation in vitamin C content as influenced by citrus genotype, duration, and storage temperature using meta-analysis approaches. Data searching, selection, and tabulation resulted in a comprehensive database constructed from 1412 data points gathered from 54 individual studies, following PRISMA-P guidelines. The vitamin C content varied widely, ranging from 0 to 76.2 mg/100 mL in whole data of citrus fruit. Meta-analysis findings revealed that the duration of storage significantly impacted the vitamin C content in citrus fruits. Specifically, for grapefruit, mandarin, and orange, the length of storage significantly influenced their vitamin C levels (P < 0.01), with a consistent decrease observed over time. The correlation coefficients (R2) were 0.63 for grapefruit, 0.9 for mandarin, and 0.69 for orange. In contrast, no significant difference was found in terms of vitamin C levels between hybrid and lime citrus concerning the impact of storage time. However, other results indicated a significant influence of storage temperature on the variation in vitamin C levels for both citrus and hybrid varieties (P < 0.001). Depending on the genotype, tangerine had significantly lower vitamin C content compared to other varieties, at 16.9 mg/100 mL, with vitamin C ranging from 13.2 to 20.9 mg/100 mL (P < 0.001). The highest vitamin C content was found in lemon and hybrid varieties, around 65.5 (range 59.3-76.2) and 48.3 (range 29.6-75.5), respectively, all in mg/100 mL (P < 0.001). Furthermore, there was a tendency for decreasing vitamin C concentration due to temperature (P = 0.078), while citrus variety experienced a decrease, although not significant. The ideal temperature (15 °C) and duration of storage (56 days) to minimize vitamin C loss in citrus fruits are at their optimum point. In conclusion, the deterioration of vitamin C in citrus fruits is influenced by both temperature and storage duration, and its content is also impacted by the variety of citrus.

Impact of ultrasound treatment on the structural modifications and functionality of carbohydrates - A review

Carbohydrates are crucial in food as essential biomolecules, serving as natural components, ingredients, or additives. Carbohydrates have numerous applications in the food industry as stabilizers, thickeners, sweeteners, and humectants. The properties and functionality of the carbohydrates undergo alterations when exposed to various thermal or non-thermal treatments. Ultrasonication is a non-thermal method that modifies the structural arrangement of carbohydrate molecules. These structural changes lead to enhanced gelling and viscous nature of the carbohydrates, thus enhancing their scope of application. Ultrasound may improve carbohydrate functionality in an environmentally sustainable way, leaving no chemical residues. The high-energy ultrasound treatments significantly reduce the molecular size of complex carbohydrates. Sonication parameters like treatment intensity, duration of treatment, and energy applied significantly affect the molecular size, depolymerization, viscosity, structural modifications, and functionality of carbohydrate biomolecules. This review provides a comprehensive analysis of ultrasound-assisted modifications in carbohydrates and the changes in functional properties induced by sonication.

Effect of coating using beeswax and sodium nitroprusside on chlorophyll stability and quality factors of lime during cold storage

Lime (Citrus floridana) is a quickly perishable fruit, limiting its shelf life because of reduced chlorophyll content and post-harvest quality under different storage conditions. To increase chlorophyll stability as well as other quality factors of limes, they were coated with beeswax in 0.1 wt.% and sodium nitroprusside in three various concentrations (0.1, 0.2, and 0.4 mM) at 25 °C for 3 min and then stored at 8 °C for 60 days. In this research, changes in weight loss, juice content, firmness (F), chlorophyll, chlorophyllase activity, polyphenol oxidase activity, color, total acidity (titratable acidity), ascorbic acid (ASA) and sensory evaluation were studied. During storage at low temperatures, BW surface coating (0.1%) alone, sodium nitroprusside alone, and also in combination with each other and a double layer were effective in maintaining chlorophyll and the qualitative characteristics of limes. In our observations, the best treatment was the treatment where the limes were coated by beeswax enriched by sodium nitroprusside coating. This treatment contained the highest content of lime juice and the highest chlorophyll plus the lowest activity of chlorophyllase and polyphenol oxidase, while the amount of green color was maintained to a large extent. As a result, it is possible to use beeswax enriched by sodium nitroprusside coating method to maintain the quality and chlorophyll of cold-stored lime fruits.

Bioactive Compounds, Antioxidant, and Antibacterial Activity Against MDR and Food-Borne Pathogenic Bacteria of Psidium guajava. L Fruit During Ripening

Psidium guajava fruits are highly appreciated for their nutrients and bioactive compounds content, which contribute to their antioxidant and antimicrobial capacities. The purpose of this study was to determine bioactive compound (phenolic, flavonoids, and carotenoid contents), antioxidant activity (DPPH, ABTS, ORAC, and FRAP), and antibacterial potential against MDR and food-borne pathogenic strains of Escherichia coli, and Staphylococcus aureus during different stages of fruit ripening.The results elucidated that ripe fruits (methanolic extract) contain the highest total phenolic, flavonoids, and carotenoid contents (417.36 ± 2.63 µg GAE/gm of FW, 711.78 ± 0.70 µg QE/gm of FW and 0.683 ± 0.06 µg/gm of FW) followed by hexane, ethyl acetate, and aqueous. Methanolic extract of the ripe fruits showed the highest antioxidant activity when measured by DPPH (61.55 ± 0.91%), FRAP (31.83 ± 0.98 mM Fe(II)/gm of FW), ORAC (17.19 ± 0.47 mM TE/ gm of FW), and ABTS (41.31 ± 0.99 µmol Trolox/gm of FW) assays. In the antibacterial assay, the ripe stage had the highest antibacterial activity against MDR and food-borne pathogenic strains of Escherichia coli, and Staphylococcus aureus. The methanolic ripe extract was found to possess maximum antibacterial activity ZOI, MIC, and IC50 18.00 ± 1.00 mm, 95.95 ± 0.05%, and 0.58 μg/ml; 15.66 ± 0.57 mm, 94.66 ± 0.19%, and 0.50 μg/ml, respectively, against pathogenic and MDR strains of E. coli and 22.33 ± 0.57 mm, 98.97 ± 0.02%, and 0.26 μg/ml; 20.33 ± 1.15 mm, 96.82 ± 0.14%, and 0.39 μg/ml, respectively, against pathogenic and MDR strains of S. aureus. Considering the bioactive compounds and beneficial effects, these fruit extracts could be promising antibiotic alternatives, avoiding antibiotic overuse and its negative effects on human health and the environment, and can be recommended as a novel functional food.

The Chemical Variability, Nutraceutical Value, and Food-Industry and Cosmetic Applications of Citrus Plants: A Critical Review

Citrus fruits occupy an important position in the context of the fruit trade, considering that both fresh fruits and processed products are produced on a large scale. Citrus fruits are recognized as an essential component of the human diet, thanks to their high content of beneficial nutrients such as vitamins, minerals, terpenes, flavonoids, coumarins and dietary fibers. Among these, a wide range of positive biological activities are attributed to terpenes and flavonoids derivatives. In this review, a list of bibliographic reports (from 2015 onwards) on the phytochemical composition, beneficial effects and potential applications of citrus fruits and their by-products is systematically summarized. In detail, information regarding the nutraceutical and medicinal value closely linked to the presence of numerous bioactive metabolites and their growing use in the food industry and food packaging, also considering any technological strategies such as encapsulation to guarantee their stability over time, were evaluated. In addition, since citrus fruit, as well as its by-products, are interesting alternatives for the reformulation of natural cosmetic products, the sector of the cosmetic industry is also explored. More in-depth knowledge of the latest information in this field will contribute to future conscious use of citrus fruits.

Ultrasound-Assisted Lactic Acid Fermentation of Bakraei (Citrus reticulata cv. Bakraei) Juice: Physicochemical and Bioactive Properties

In this study, ultrasonication (US) (50 W, 30 kHz, 1–6 min) was used to increase the efficiency of Limosilactobacillus reuteri PTCC 1655 fermentation process (37 °C; 30 h) of Bakraei juice. Total sugars, pH, Brix, organic acids, vitamin C, polyphenols, antioxidant activity, α-amylase inhibition and anti-inflammatory properties were measured during the fermentation period. The results showed that by increasing the ultrasound time up to 5 min, pH, vitamin C, citric acid, and polyphenolic compounds decreased, while lactic acid, antioxidant capacity, α-amylase inhibition and anti-inflammatory properties were increased. When the ultrasound time was increased up to 6 min, compared to the non-ultrasound-treated sample, the efficiency of the fermentation process decreased and promoted a decrease in the microbial population, lactic acid levels, antioxidant activity, α-amylase inhibition, and anti-inflammatory properties of the juices. The initial anti-inflammatory activity (11.3%) of juice reached values of 33.4% and 19.5%, after US treatments of 5 and 6 min, respectively, compared to the non-sonicated juice (21.7%), after 30 h of fermentation. As a result, the use of ultrasound in the controlled fermentation process can increase the efficiency of fermentation process.

Effect of High-Pressure Processing (HPP) on Phenolics of North Atlantic Sea Cucumber (Cucumaria frondosa)

Sea cucumber contains a wide range of bioactive compounds, including phenolics. This study investigated the free, esterified, and insoluble-bound phenolics of sea cucumber body wall as affected by high-pressure processing (HPP) pretreatment. Sea cucumber body wall was subjected to HPP (200, 400, and 600 MPa for 5, 10, and 15 min), followed by the extraction of phenolics. The contents of total phenolics and antioxidant activity were monitored. Compared to untreated samples, those treated with HPP exhibited significantly higher total phenolics, flavonoids, and antioxidant activities. Treatment of 600 MPa for 10 min offered the optimal results. The highest amount of phenolics was observed in the free phenolic fraction, followed by esterified and insoluble-bound phenolic fractions. Moreover, phenolic extracts showed inhibitory effects against cupric ion-induced low-density lipoprotein (LDL)-cholesterol oxidation, peroxyl and hydroxyl radical-induced DNA scission, α-glucosidase activity, and formation of advanced glycation end products (AGEs). Ultra-high-performance liquid chromatography equipped with a quadrupole time of fight and mass spectrometer (UHPLC-QTOF-MS/MS) identified 20 phenolic compounds, mainly phenolic acids and flavonoids, from the body wall of this species for the first time. Thus, sea cucumber may lead to the production of a multitude of value-added products.

High-Pressure Processing for Sustainable Food Supply

Sustainable food supply has gained considerable consumer concern due to the high percentage of spoilage microorganisms. Food industries need to expand advanced technologies that can maintain the nutritive content of foods, enhance the bio-availability of bioactive compounds, provide environmental and economic sustainability, and fulfill consumers’ requirements of sensory characteristics. Heat treatment negatively affects food samples’ nutritional and sensory properties as bioactives are sensitive to high-temperature processing. The need arises for non-thermal processes to reduce food losses, and sustainable developments in preservation, nutritional security, and food safety are crucial parameters for the upcoming era. Non-thermal processes have been successfully approved because they increase food quality, reduce water utilization, decrease emissions, improve energy efficiency, assure clean labeling, and utilize by-products from waste food. These processes include pulsed electric field (PEF), sonication, high-pressure processing (HPP), cold plasma, and pulsed light. This review describes the use of HPP in various processes for sustainable food processing. The influence of this technique on microbial, physicochemical, and nutritional properties of foods for sustainable food supply is discussed. This approach also emphasizes the limitations of this emerging technique. HPP has been successfully analyzed to meet the global requirements. A limited global food source must have a balanced approach to the raw content, water, energy, and nutrient content. HPP showed positive results in reducing microbial spoilage and, at the same time, retains the nutritional value. HPP technology meets the essential requirements for sustainable and clean labeled food production. It requires limited resources to produce nutritionally suitable foods for consumers’ health.

Optimization of the Multienzyme-Assisted Extraction Procedure of Bioactive Compounds Extracts from Common Buckwheat (Fagopyrum esculentum M.) and Evaluation of Obtained Extracts

Optimization of the extraction procedure using a multienzymes cocktail for common buckwheat (Fagopyrum esculentum M.) is important due to the yield, fermentable sugars, oligosaccharides and bioactive compounds for creating higher added value products. This study was undertaken to find out the optimum multienzymes-water extraction on yield and total phenolic compounds for common Buckwheat using response surface methodology (RSM). Three independent variables, time (2, 13, and 24 h), temperature (60 °C, 70 °C, 80 °C), and non-starch polysaccharide (NSP) enzymes mixture (0.10, 0.55, and 1.00 mL), were analyzed to optimize the response variables. NSP hydrolyzing enzymes, cellulase, xylanase, and β-glucanase, were produced by Trichoderma reesei. Estimated optimum conditions for F. esculentum were found: time-2 h, temperature-65 °C, and cellulase activity-8.6 CellG5 Units/mL. Different optimization run samples were collected and lyophilized for further analysis until the hydrophilic property using the water contact angle methodology and rutin content using HPLC was determined. Results indicated NSP enzymes activity did not differ between water contact angles after 13 h of enzymatic water extraction. However, longer fermentation time (24 h) decreased static water contact angle by approximately 3-7° for lyophilized water extract and 2-7° for solid fraction after fermentation. It implies enzymatic hydrolysis during water extraction increased hydrophilic properties in solid fraction and decreased hydrophilicity in water fraction due to the enzymes cleaved glycosidic bonds releasing water-soluble compounds.

Evaluation of the Health-Promoting Properties of Selected Fruits

In this study, the health-promoting benefits of different fruits grown in Madeira Island, namely lemon (Citrus limon var. eureka), tangerine (Citrus reticulata var. setubalense), pitanga (Eugenia uniflora var. red), tomato (Solanum lycopersicum var. gordal) and uva-da-serra, an endemic blueberry (Vaccinium padifolium Sm.), were investigated. The phenolic composition (total phenolics and total flavonoids content) and antioxidant capacity (assessed through ABTS and DPPH assays) were measured revealing a high phenolic potential for all fruits, except tomato, while uva-da-serra is particularly rich in flavonoids. In relation to the antioxidant capacity, the highest values were obtained for pitanga and uva-da-serra extracts. The bioactive potential was also assessed through the ability of the extracts to inhibit digestive enzymes linked to diabetes (α-amylase, α- and β-glucosidases) and hypertension (angiotensin-converting enzyme, ACE). The results obtained point to a very high bioactive potential with the selected samples exhibiting very important ACE anti-enzymatic capacities. A statistical analysis of the obtained data reveals a very strong correlation between ABTS and TPC, and a strong contribution of the fruit polyphenols for enzyme inhibition, and thus, presenting high antihypertensive and antidiabetic capacities. Overall, the results obtained clearly show a high bioactive potential of the selected fruits that should be further studied, in terms of specific phenolic composition. Moreover, these results strongly support the valorisation of pitanga seeds usually discarded as a waste, and uva-da-serra, an endemic and wild bush, as potential bioresources of bioactive compounds with impact in human diet.

Valorization of Citrus Co-Products: Recovery of Bioactive Compounds and Application in Meat and Meat Products

Citrus fruits (orange, lemon, mandarin, and grapefruit) are one of the most extensively cultivated crops. Actually, fresh consumption far exceeds the demand and, subsequently, a great volume of the production is destined for the citrus-processing industries, which produce a huge quantity of co-products. These co-products, without proper treatment and disposal, might cause severe environmental problems. The co-products obtained from the citrus industry may be considered a very important source of high-added-value bioactive compounds that could be used in the pharmaceutical, cosmetic, and dietetic industries, and mainly in the food industry. Due to consumer demands, the food industry is exploring a new and economical source of bioactive compounds to develop novel foods with healthy properties. Thus, the aim of this review is to describe the possible benefits of citrus co-products as a source of bioactive compounds and their applications in the development of healthier meat and meat products.

Food Waste Biorefinery: Pathway towards Circular Bioeconomy

Food waste biorefineries for the production of biofuels, platform chemicals and other bio-based materials can significantly reduce a huge environmental burden and provide sustainable resources for the production of chemicals and materials. This will significantly contribute to the transition of the linear based economy to a more circular economy. A variety of chemicals, biofuels and materials can be produced from food waste by the integrated biorefinery approach. This enhances the bioeconomy and helps toward the design of more green, ecofriendly, and sustainable methods of material productions that contribute to sustainable development goals. The waste biorefinery is a tool to achieve a value-added product that can provide a better utilization of materials and resources while minimizing and/or eliminating environmental impacts. Recently, food waste biorefineries have gained momentum for the production of biofuels, chemicals, and bio-based materials due to the shifting of regulations and policies towards sustainable development. This review attempts to explore the state of the art of food waste biorefinery and the products associated with it.

Membrane Filtration-Assisted Enzymatic Hydrolysis Affects the Biological Activity of Potato Juice

The results of recently published studies indicate that potato juice is characterized by interesting biological activity that can be particularly useful in the case of gastrointestinal symptoms. Moreover, the studies also described the high nutritional value of its proteins. This article is a report on the impact of the enzymatic hydrolysis of proteins combined with membrane filtration. The obtained potato juice protein hydrolysate (PJPH) and its concentrate (cPJPH) were characterized in terms of their nutritional value and biological activity. The amino acid profile and scoring, the content of mineral compounds, and the antioxidant and in vitro cytotoxic activity were assessed. The study proved that the antioxidant activity of PJPH is higher than that of fresh potato juice, and the cytotoxicity against human gastric carcinoma cell line (Hs 746T), human colon cancer cell line (Caco-2), human colorectal adenocarcinoma cell line (HT-29), and human normal colon mucosa cell line (CCD 841 CoN) showed biological activity specifically targeted against cancer cells. Therefore, it can be concluded that the membrane filtration-assisted enzymatic hydrolysis of potato juice proteins may increase their biological activity and allow for potato juice to be used in the production of medicinal preparations.