Impact of washing and freezing on nutritional composition, bioactive compounds, antioxidant activity and microstructure of mango peels.

Mango peels are widely produced and highly perishable. Disinfectant washing and freezing are among the most used methods to preserve foods. However, their impact on products' properties is conditioned by the foods' features. This study evaluated for the first time the phytochemical composition, antioxidant activity, and microstructure of mango peels washed with peracetic acid (27 mg/mL for 19 min) and frozen at -20 °C for 30 days. Washing decreased the content of vitamin C (-7%), penta-O-galloyl-ß-d-glucose (-23 %), catechin (-30 %), and lutein (-24 %), but the antioxidant activity was preserved. Freezing changed mango peels' microstructure, increased free phenolic compounds, namely acid gallic (+36 %) and catechin (+51 %), but reduced bound phenolic compounds (-12 % to -87 %), bound phenolic compounds' antioxidant activity (-51 % to -72 %), and violaxanthin (-51 %). Both methods were considered adequate to conserve mango peels since fiber and the main bioactive compounds (free mangiferin, free gallic acid, and ß-carotene) remained unchanged or increased.

Innovative Processing Technologies to Develop a New Segment of Functional Citrus-Based Beverages: Current and Future Trends.

The food industries are interested in developing functional products due to their popularity within nutritional and healthy circles. Functional fruit-based beverages represent one of the fast-growing markets due to the high concentrations of bioactive compounds (BCs), which can be health promoters. Hence, functional beverages based on citrus fruits are a potential way to take advantage of their nutritional and bioactive properties that could attract the interest of consumers. In order to ensure microbial and quality stability, the beverages are subjected to preservation treatment; however, the application of high temperatures leads to the loss of thermolabile BCs. Nowadays, innovative processing technologies (IPT) such as pulsed electric field (PEF), high-pressure processing (HPP), ultrasound processing (US), ohmic heating (OH), and microwave (MW) are a promising alternative due to their efficiency and low impact on juice BCs. The available literature concerning the effects of these technologies in functional fruit-based beverages is scarce; thus, this review gathers the most relevant information about the main positive and negative aspects of the IPT in functional properties, safety, and consumer acceptance of functional citrus-based beverages, as well as the use of citrus by-products to promote the circular economy in citrus processing.

Polyelectrolyte Precipitation: A New Green Chemistry Approach to Recover Value-Added Proteins from Different Sources in a Circular Economy Context.

Proteins have always been vital biological molecules used for industrial purposes, human nutrition and health. Nowadays, seeking new alternatives and sources of these biomolecules is becoming an increasing research trend derived from the present consumer awareness between food consumption and health promotion, but also on environmental sustainability. Although there are different consolidated/traditional downstream processes to obtain proteins, such as chromatography tools, alkali hydrolysis, precipitation by inorganic salts and organic solvents, their industrial-scale application still demands urgent innovation due to the poor recovery yields, high costs and time-consuming steps, environmental impact as well as some toxic concerns. Polyelectrolyte precipitation represents a green, innovative alternative for protein recovery; however, there are reduced data regarding its pilot or industrial-scale application. In this literature work, the action mechanism and principles with regards to its functionality and insights for its application on a big scale are reviewed. Overall, this review discusses the novelty and sustainability of protein precipitation by polyelectrolytes from different sources against traditional techniques as well as highlights the relationship between protein source, production relevance and bioactive properties that are key factors to maximize the application of this extractive method on a circular economy context.

Impact of Circular Brewer's Spent Grain Flour after In Vitro Gastrointestinal Digestion on Human Gut Microbiota.

Brewer's spent grain (BSG) solid residues are constituted by dietary fibre, protein, sugars, and polyphenols, which can have potential effects on human health. In this study, for the first time, the flours obtained from solid residues of solid-liquid extraction (SLE) and ohmic heating extraction (OHE) were applied throughout the gastrointestinal digestion simulation (GID), in order to evaluate their prebiotic potential and in vitro human gut microbiota fermentation. The results showed that the digestion of BSG flours obtained by the different methods lead to an increase throughout the GID of total phenolic compounds (SLE: from 2.27 to 7.20 mg gallic acid/g BSG-60% ethanol:water (v/v); OHE: 2.23 to 8.36 mg gallic acid/g BSG-80% ethanol:water (v/v)) and consequently an increase in antioxidant activity (ABTS-SLE: from 6.26 to 13.07 mg ascorbic acid/g BSG-80% ethanol:water (v/v); OHE: 4.60 to 10.60 mg ascorbic acid/g BSG-80% ethanol:water (v/v)-ORAC-SLE: 3.31 to 14.94 mg Trolox/g BSG-80% ethanol:water (v/v); OHE: from 2.13 to 17.37 mg Trolox/g BSG-60% ethanol:water (v/v)). The main phenolic compounds identified included representative molecules such as vanillic and ferulic acids, vanillin and catechin, among others being identified and quantified in all GID phases. These samples also induced the growth of probiotic bacteria and promoted the positive modulation of beneficial strains (such as Bifidobacterium spp. and Lactobacillus spp.) present in human faeces. Moreover, the fermentation by human faeces microbiota also allowed the production of short chain fatty acids (acetic, propionic, and butyric). Furthermore, previous identified polyphenols were also identified during fecal fermentation. This study demonstrates that BSG flours obtained from the solid residues of SLE and OHE extractions promoted a positive modulation of gut microbiota and related metabolism and antioxidant environment associated to the released phenolic compounds.

Comparative Analysis between Synthetic Vitamin E and Natural Antioxidant Sources from Tomato, Carrot and Coriander in Diets for Market-Sized Dicentrarchus labrax.

Synthetic vitamin E is commonly used in aquafeeds to prevent oxidative stress in fish and delay feed and flesh oxidation during storage, but consumers' preferences tend towards natural antioxidant sources. The potential of vegetable antioxidants-rich coproducts, dried tomato (TO), carrot (CA) and coriander (CO) was compared to that of synthetic vitamin E included in diets at either a regular (CTRL; 100 mg kg-1) or reinforced dose (VITE; 500 mg kg-1). Natural antioxidants were added at 2% to the CTRL. Mixes were then extruded and dried, generating five experimental diets that were fed to European sea bass juveniles (114 g) over 12 weeks. Vitamin E and carotenoid content of extruded diets showed signs of degradation. The experimental diets had very limited effects on fish growth or body composition, immunomodulatory response, muscle and liver antioxidant potential, organoleptic properties or consumer acceptance. Altogether, experimental findings suggest that neither a heightened inclusion dose of 500 mg kg-1 of vitamin E, nor a 2% inclusion of natural antioxidants provided additional antioxidant protection, compared to fish fed diets including the regular dose of 100 mg kg-1 of vitamin E.

Prebiotic effect, bioactive compounds and antioxidant capacity of melon peel (Cucumis melo L. inodorus) flour subjected to in vitro gastrointestinal digestion and human faecal fermentation.

Melon peels are by-products derived from food processing industries, representing potential sources of new ingredients in particular dietary fibre and phenolic compounds, which in synergy could exert beneficial effects on human health. The objective of this study was to evaluate the accessibility of bioactive compounds from melon peels throughout gastrointestinal digestion and evaluate their prebiotic effect when submitted to in vitro human faecal fermentation. Melon peels flour obtained from solid fraction showed an increase in antioxidant capacity at the gastric and intestinal phase, which was corroborated by the total phenolic content (126.91%) increase and the identified individual phenolics (tyrosol, luteolin-6-glycoside, chlorogenic and caffeic acids). Also, melon peels flour positively impacted the gut microbiota diversity, showing a similar ratio of Firmicutes/Bacteroidetes compared to the positive control (FOS) and promoted the production of short-chain fatty acids, mainly acetate > propionate > butyrate. Thus, these findings demonstrate that melon peels have antioxidant and prebiotic potential attributed to the phenolic compounds and the production of beneficial fatty acids, which could improve human gut health.

Impact of Simulated Human Gastrointestinal Digestion on the Bioactive Fraction of Upcycled Pineapple By-Products.

Pineapple by-products (peels and stems) from fruit processing industries were evaluated to understand its potential application as a functional food. Therefore, the bioactive compounds of pineapple by-products were characterized for prebiotic and antioxidant activities. A total characterization of soluble carbohydrates profile (simples and complex carbohydrates), as well as polyphenols was performed, after removal of enzymatic fraction from pineapple crude juice, allowing the decrease of proteolytic activity and improving the other biological activities. Results showed that pineapple liquid fraction, from stem and peels, can be applied as a prebiotic enhancer, promoting the growth of five probiotic microorganisms (two strains of Lactobacillus sp. and three strains of Bifidobacterium sp.), as a single carbohydrate source. Moreover, through HPLC (High Performance Liquid Chromatography) analysis, 10 polyphenols were identified in pineapple liquid fractions, with some expected differences between both evaluated by-products. Gastrointestinal tract was simulated, in a continuous mode to understand the impact of pH changes and gastrointestinal enzymes into pineapple liquid fractions. Results showed a digestion of high molecular weight polysaccharides into small molecular weight tri-, di-, and monosaccharides. There was an increase of samples antioxidant activity through the gastrointestinal stage, followed by the release of specific polyphenols, such as chlorogenic, coumaric, and ferulic acids. The prebiotic activity did not improve throughout the simulation, in fact, the prebiotic potential decreased throughout the different stages.

Impact of Processing Approach and Storage Time on Bioactive and Biological Properties of Rocket, Spinach and Watercress Byproducts.

The high nutritional value of vegetables is well recognized, but their short shelf life and seasonal nature result in massive losses and wastes. Vegetable's byproducts are an opportunity to develop value-added ingredients, increasing food system efficiency and environmental sustainability. In the present work, pulps and powders of byproducts from rocket and spinach leaves and watercress were developed and stored for six months under freezing and vacuum conditions, respectively. After processing and storage, microbiological quality, bioactive compounds (polyphenols, carotenoids and tocopherols profiles), antioxidant capacity, and pulps viscosity were analyzed. Generally, the developed vegetable's pulps and powders were considered microbiologically safe. Although some variations after processing and storage were verified, the antioxidant activity was preserved or improved. A rich phenolic composition was also registered and maintained. During freezing, the quantitative carotenoid profile was significantly improved (mainly in rocket and spinach), while after drying, there was a significant decrease. A positive effect was verified in the vitamin E level. Both processing and storage conditions resulted in products with relevant phenolics, carotenoids and tocopherol levels, contributing to the antioxidant activity registered. Thus, this study demonstrates the potential of vegetable byproducts valorization through developing these functional ingredients bringing economic and environmental value into the food chain.

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.

Optimization of Natural Antioxidants Extraction from Pineapple Peel and Their Stabilization by Spray Drying.

Pineapple peel still contains an important amount of phenolic compounds and vitamins with valuable antioxidant activity. In this way, the aim of this study was the recovery of the bioactive compounds from pineapple peel using environmentally friendly and low-cost techniques, envisaging their application in food products. From the solid-liquid extraction conditions tested, the one delivering an extract with higher total phenolic content and antioxidant capacity was a single extraction step with a solvent-pineapple peel ratio of 1:1 (w/w) for 25 min at ambient temperature, using ethanol-water (80-20%) as a solvent. The resulting extract revealed a total phenolic content value of 11.10 ± 0.01 mg gallic acid equivalent (GAE)/g dry extract, antioxidant activity of 91.79 ± 1.98 µmol Trolox/g dry extract by the DPPH method, and 174.50 ± 9.98 µmol Trolox/g dry extract by the FRAP method. The antioxidant rich extract was subjected to stabilization by the spray drying process at 150 °C of inlet air temperature using maltodextrin (5% w/w) as an encapsulating agent. The results showed that the antioxidant capacity of the encapsulated compounds was maintained after encapsulation. The loaded microparticles obtained, which consist of a bioactive powder, present a great potential to be incorporated in food products or to produce bioactive packaging systems.

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, ß-carotene, lutein, ß-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.

Management of Fruit Industrial By-Products-A Case Study on Circular Economy Approach.

The management of industrial fruit by-products is important not only to decrease the volume of food waste accumulated in the landfills but also to develop strategies through reuse with the purpose to valorise and add economic value. The disposal of food waste leads to different global issues in different sectors, such as social, environmental and economical. These by-products represent a rich source of valuable compounds (polyphenols) with high antioxidant activity, which can be extracted through biotechnological methodologies for future industrial applications. In this context, the management of fruit by-products is challenged to move from a linear economy to a circular economy. Therefore, the purpose of this review is to provide a critical view of an integrated valorisation of fruit by-products to overcome a global issue, via the production of antioxidant extracts with high economic value. A case study of pineapple processing industrialization in a circular economy is explored and discussed.

Integral Valorization of Pineapple (Ananas comosus L.) By-Products through a Green Chemistry Approach towards Added Value Ingredients.

Industrial by-products are produced every day through fruit processing industries. Pineapple is not an exception; when processed, around 60% (w/w) of its weight are peels, stem, trimmings, and crown, the only used fruit part for human consumption. Due to high concerns of sustainability in the food system and negative high impact of human practice in the environment, a strategy has to be developed. Therefore, a green chemistry approach was applied to pineapple by-products to make an integrated valorization by the extraction of bioactive molecules. Two pineapple by-products (peels and stems) were studied, applying a green chemistry approach, which means the non-use of organic solvents or extreme methodologies. A subdivision of each by-product was done by the application of a juice machine. The peels and stems in the fresh state were ground separately, creating two fractions for each by-product-a juice and a wet pulp (press cake). The press cake was characterized, dried, and ground to create a fine powder flour. To the juice, a precipitation methodology with polysaccharides was applied, which allowed the bromelain separation (developing of an enzymatic fraction) from the fruit juice. The enzymatic extract was freeze-dried, and the juice was spray-dried, developing two more fine powders. Thus, three new ingredients were produced from each by-product, creating a total of six new ingredients. Overall, the enzymatic fractions represented around 0.26% (w/w) of pineapple weight. Pineapple stem juice represented 4.8% (w/w), and peel juice represented 17.3% (w/w). Pineapple stem flour represented 3.1% (w/w), and peel flour represented 11.4% (w/w) of the total pineapple weight. To valorize the by-products juices, a full characterization was performed of bioactive molecules and biological activities. When comparing the two juices, the peel juice showed lower content of total phenolic compounds, lower antioxidant capacity, and lower content of vitamin C. The different phenolic compounds were identified by HPLC analysis in the two pineapple by-products juices. However, the same compounds in both juices were quantified (chlorogenic, caffeic, and ferulic acids). On the other hand, the by-products flours had a high content of insoluble dietary fiber (IDF), mainly cellulose and hemicellulose. Therefore, the approach applied in this work opens the door to the production of green products, as a result of by-products valorization. This could be applied not only in the food industry but also in the nutraceutical and cosmetic industries.

Enzymatic soy protein hydrolysis: A tool for biofunctional food ingredient production.

This work aimed to evaluate the digestive stability of the peptides previously identified from a Corolase PP soy protein hydrolysate (SPH) and to respond to the uncertainty about the merit of controlled hydrolysis. For this purpose, we applied an empirical and theoretical analysis, determining peptide sequences, oxygen radical scavenging (ORAC) and ACE inhibitory (iACE) activities, and the effect of hydrolysis on solubility. Results showed that during digestion most of SPH peptides were degraded as smaller ones. However, both SPH bioactivities improved significantly after digestion (3.9 ±â€¯0.1 µmol TE/mg protein for ORAC and IC50 = 52 ±â€¯4µg protein/mL for iACE) with similar values for soy protein isolate (SPI). With respect to solubility, the controlled hydrolysis considerably increased this functional property. In conclusion, the results indicated that controlled enzymatic hydrolysis of SPI with Corolase PP produced an ingredient more apt to be incorporated in certain nutritional or nutraceutical formulations.

Safety profile of solid lipid nanoparticles loaded with rosmarinic acid for oral use: in vitro and animal approaches.

Rosmarinic acid (RA) possesses several protective bioactivities that have attracted increasing interest by nutraceutical/pharmaceutical industries. Considering the reduced bioavailability after oral use, effective (and safe) delivery systems are crucial to protect RA from gastrointestinal degradation. This study aims to characterize the safety profile of solid lipid nanoparticles produced with Witepsol and Carnauba waxes and loaded with RA, using in vitro and in vivo approaches, focused on genotoxicity and cytotoxicity assays, redox status markers, hematological and biochemical profile, liver and kidney function, gut bacterial microbiota, and fecal fatty acids composition. Free RA and sage extract, empty nanoparticles, or nanoparticles loaded with RA or sage extract (0.15 and 1.5 mg/mL) were evaluated for cell (lymphocytes) viability, necrosis and apoptosis, and antioxidant/prooxidant effects upon DNA. Wistar rats were orally treated for 14 days with vehicle (control) and with Witepsol or Carnauba nanoparticles loaded with RA at 1 and 10 mg/kg body weight/d. Blood, urine, feces, and several tissues were collected for analysis. Free and loaded RA, at 0.15 mg/mL, presented a safe profile, while genotoxic potential was found for the higher dose (1.5 mg/mL), mainly by necrosis. Our data suggest that both types of nanoparticles are safe when loaded with moderate concentrations of RA, without in vitro genotoxicity and cytotoxicity and with an in vivo safety profile in rats orally treated, thus opening new avenues for use in nutraceutical applications.

Insights into the protective role of solid lipid nanoparticles on rosmarinic acid bioactivity during exposure to simulated gastrointestinal conditions.

The evaluation of the digestion effects on bioactive solid lipid nanoparticles (SLN) was performed. For this purpose, witepsol and carnauba SLN loaded with rosmarinic acid (RA) were exposed to the simulated gastrointestinal tract (GIT) conditions prevailing in stomach and small intestine. The simulation of intestinal epithelium was made with a dialysis bag and intestinal cell culture lines. Changes on SLN physical properties, RA release and absorption profiles were followed at each step. Combination of digestion pH and enzymes showed a significant effect upon SLN physical properties. Zeta potential values increased at stomach conditions and decreased at small intestine simulation. Also, at intestine, SLN increased their sizes and released 40-60% of RA, maintaining its initial antioxidant activity values. Sustained release of 40% of RA from SLN was also observed in dialysis tube. At CaCo-2 cell line, both types of SLN showed similar absorbed RA % (ca. 30%). Nevertheless, in CaCo-2/HT29x mix cell lines, for carnauba SLN a lower adsorption RA % was observed than for witepsol SLN. Solid lipid nanoparticles protected RA bioactivity (in terms of antioxidant activity) until reaching the intestine. A controlled release of RA from SLN was achieved and a significant absorption was observed at intestinal cells. Overall, SLN produced with witepsol showed a higher stability than carnauba SLN.

Optimization of the production of solid Witepsol nanoparticles loaded with rosmarinic acid.

During the last decade there has been a growing interest in the formulation of new food and nutraceutical products containing compounds with antioxidant activity. Unfortunately, due to their structure, certain compounds such as polyphenols, in particular rosmarinic acid (RA) are not stable and may interact easily with matrices in which they are incorporated. To overcome such limitations, the formulation of loaded polyphenols nanoparticles can offer an efficient solution to protect such compounds. Based on this rationale, the aim of this study was to prepare solid lipid nanoparticles (SLNs) loaded with RA using a hot melt ultrasonication method, where Witepsol H15 was used as lipid and Polysorbate 80 (Tween 80) as surfactant, following a 3(2) fractional factorial design, resulting in the use of 3 different percentages of surfactant (viz. 1, 2 and 3%, v/v) and lipid (0.5, 1.0 and 1.5%, w/v). The stability of the nanoparticles systems were tested during 28 d in aqueous solution stored at refrigeration temperature (ca. 5 °C), tracking the mean particle size of different formulations by photon correlation spectroscopy. To confirm RA entrapment, thermal analyses of the nanoparticles by DSC and FTIR were performed. The association efficiencies percentages (AE%) were determined using HPLC to quantitatively assess the RA in supernatants. Results showed that Witepsol H15 produced nanoparticles with initial mean diameters between 270 and 1000 nm, yet over time, a slight increase occurred, but without occurrence of aggregation. The AE% showed a high percentage of encapsulation (ca. 99%), which reveals low polyphenol releases from SLNs throughout storage time. In general, results showed a successful production of SLNs with properties that can be used to food applications.

Study of antimicrobial activity and atomic force microscopy imaging of the action mechanism of cashew tree gum.

The aim of this work was to evaluate the antimicrobial potential of two grades of cashew tree gum (crude and purified) against eight microorganisms and to analyze the mechanism of cashew tree gum antimicrobial action via atomic force microscopy (AFM) imaging. The results indicated strong antimicrobial properties of pure cashew tree gum against all tested microorganisms, except for Candida albicans and Lactobacillus acidophilus. On the other hand crude cashew gum showed antimicrobial activity only against Gram-positive bacteria (MRSA, MSSA, Listeria innocua and Enterococcus faecium). Atomic force microscopy imaging showed that pure cashew tree gum lead to bacterial cell collapse. In conclusion cashew tree gum presented relevant antimicrobial activity against most of the studied bacteria, and the purification of the cashew gum affected its antimicrobial spectrum.