Fruit and vegetable processing industry is one of the relevant generators of food by-products, which display limited commercial exploitation entailing economic and environmental problems. However, ...these by-products present a considerable amount of dietary fiber as well as bioactive compounds with important biological activities such as antioxidant and antimicrobial properties. Therefore, the international scientific community has considered the incorporation of their extracts or powders to preserve or fortify food products an area of interest, mainly because nowadays consumers demand the production of safer and health-promoting foods. In the present review, several statistical and other relevant data concerning the increasing generation of fruit and vegetable by-products (FVB) are critically analyzed and presented. Next, a special focus is given to the chemical characterization and bioactivities (namely antioxidant and antimicrobial properties) of several FVB. Lastly, an in-depth review with recent studies (briefly compiled) about the incorporation of fruit and vegetable processing wastes in animal, dairy, beverages, and bakery products, among others is provided.
Extraction is the first step for isolation and purification of interesting bioactive compounds, by mixing of the plant material with an adequate solvent. Those bioactive compounds are, usually, ...secondary metabolites, such as phenolic acids and flavonoids which are present in closed insoluble structures, making its extraction a challenge. There are many different traditional extraction methods, such as Soxhlet, heat reflux, and maceration. Nevertheless, due to several disadvantages, they are being replaced by new methods, using emergent technologies, such as high hydrostatic pressure, ultrasounds, pulsed electric fields, and supercritical fluids. The use of novel technologies allows enhancing mass transfer rates, increasing cell permeability as well as increasing secondary metabolite diffusion, leading to higher extraction yields, fewer impurities on the final extract, extractions at room temperature with thermo-sensitive structures preservation, use of different non-organic solvents, low energy consumption, short operation time, and have no significant or lower effect on the structure of bioactive compounds. This paper aims to review the effect of the main emergent extraction technologies (high hydrostatic pressure, pulsed electric fields, ultrasounds, and supercritical fluid assisted) on the individual profile of bioactive compounds from plant material.
Display omitted
•Conventional extractions methods present several disadvantages.•Non-thermal technologies are in development to enhance the extraction process.•These new methods are more efficient for bioactive compounds extraction.•Non-thermal extraction technologies allow to preserve heat-labile compounds.
•Effect of strawberry addition in nutritional and functional properties of yoghurt.•Antioxidant capacity of strawberry pulp was reduced after addition in yoghurt.•Yoghurt showed important decrease of ...polyphenols and whey proteins along storage.•The behaviour of specific phenolics and proteins were different throughout storage.•Potential interaction between proteins, hydrocolloid and polyphenols was observed.
An immediate decrease in the total antioxidant activity (23%) and total phenolic content (14%) was observed after addition of strawberry preparations to yoghurt. The total anthocyanin content did not change immediately, but decreased 24% throughout the yoghurt shelf-life.
The individual compounds, (+)-catechin (60%), (−)-epicatechin (60%), kaempferol (33%) and quercetin-3-rutinoside (29%) decreased after 24h in the yoghurt made with the strawberry preparation. During the remaining period of storage these compounds increased by 47%, 6%, 4% and 18%, respectively. Pelargonidin-3-glucoside decreased 49% after 28d.
Immediately after the addition of the strawberry preparation to yoghurt, β-lactoglobulin decreased to values lower than the limit of detection and α-lactalbumin by approximately 34%, and was reduced further slowly throughout yoghurt self-life. An immediate interaction between the carrageenan present in the strawberry preparation and β-LG was observed. The variations of both polyphenols and protein in the presence of carrageenan and the potential interactions were discussed.
This study aimed to assess the effect of high pressure (300 and 600 MPa) and enzymatic extraction (pectinase and cellulase) on the phenolic compounds profile, antioxidant capacity and antimicrobial ...activity of extracts from pomegranate by-products. Antimicrobial activity against eight different strains of pathogenic and contaminant bacteria and against five beneficial bacteria including Lactobacillus and Bifidobacterium strains were determined.
The maximum level of total phenolic content, as well as antioxidant capacity were observed at 300 MPa, however enzymatic extraction did not improve the extraction yields. Punicalagin isomers and bis-hexahydroxydiphenoyl-glucoside isomer were the most abundant phenolic compounds found in the extracts. All pomegranate peel extracts demonstrated selective antimicrobial activity against all pathogenic bacteria without affecting beneficial ones. Pressurized extracts presented lower minimum inhibitory concentration against Bacillus cereus and Pseudomonas aeruginosa and lower minimum bactericidal concentration against B. cereus, while, enzymatic extracts presented lower minimum bactericidal concentration for Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus and Listeria monocytogenes. Principal component analyses reveled that antioxidant activity and phenolic compounds content were strongly related with antimicrobial activity. Pomegranate peels extracts obtained by high pressure extraction could so be used as a source of high added-value bioactive compounds for antioxidant and antimicrobial applications.
Display omitted
•High pressure improved bioactive phenolic compounds extraction from pomegranate peel.•Total phenolic content and antioxidant activity showed maximum values at 300 MPa.•Extracts showed antimicrobial activity towards pathogens but none on lactic acid bacteria.•Gram-positive bacteria were more sensitive than Gram-negative bacteria.•Punicalagin isomers were the most abundant phenolic compound found in all extracts.
► Non-thermal and sanitizer processes effects were studied on chilled strawberries. ► Hydrogen peroxide reduced microbial loads but lead to losses on quality attributes. ► Ozone and ultrasounds were ...efficient in controlling initial microbial contamination. ► Those technologies lead to products with satisfactory quality retention. ► These are promising alternatives to thermal processes.
The effect of non-thermal technologies (ozone in aqueous solution, ultrasound and ultraviolet C radiation) and washings with chemical solutions (sodium hypochlorite and hydrogen peroxide) on safety and quality features of strawberries was studied. These treatments were applied before fruit storage at two different temperatures (4 and 15°C). The overall impact on microbial loads (total mesophiles, and yeasts and moulds) and selected quality attributes (colour, firmness, pH, total anthocyanins and ascorbic acid content) was assessed.
During storage under refrigerated temperature, washing with hydrogen peroxide solutions resulted in strawberries with lower microbial loads, when compared to the other treatments. However, it produced significant key quality attributes losses, such as colour and total anthocyanins content.
The results presented show that ozone and ultrasound are promising alternatives to thermal treatments. The application of such technologies, before refrigerated storage of strawberries, allowed a satisfactory retention of all quality characteristics analysed, while being efficient in controlling microbial contamination.
Agro-industrial by-products and by-products from the wine industry (pomace, peels, leaves, stems, and seeds) represent a potential economic interest because they are usually relevant natural sources ...of bioactive compounds, which may present significant biological activities related to human health and well-being. This article aims to review wine and winery industry by-products as potential natural sources of antioxidant, antimicrobial, anti-inflammatory, antiaging, and anticancer compounds, as well as briefly highlighting the extraction methods used to obtain these bioactive compounds and explore their potential applications in the food, cosmetic, and packaging industries. Although there are some studies of wine industry by-products with different origins, this revision will be mainly focused on the Portuguese vineyard industry since it represents an import industrial sector as proof of the diversity of the bioactive compounds identified. Therefore, the recovery of these bioactive molecules that act as antioxidants and health-promoting agents may promote a variety of industries at the same time as the circular economy.
High-pressure assisted extraction was employed to obtain fig by-product derived extracts and its impact was evaluated on antioxidant activity and total phenolic, tannin, and flavonoid. A Box–Behnken ...design was applied to evaluate the effects of pressure, extraction time and ethanol concentration on extractions and optimal conditions were estimated by response surface methodology. The correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be employed to optimize the high pressure extraction of compounds. Only the models developed for total antioxidant activity by DPPH
·
and for total flavonoids presented coefficient determinations lower than 0.95. From response surface plots, pressure, extraction time and ethanol concentration showed independent and interactive effects. The optimal conditions included 600 MPa, an extraction time between 18 and 29 min, depending on the parameter analyzed and a low ethanol concentration (<15%) except for flavonoids (48%). High pressure led to an increase of 8–13% of antioxidant activity and an increase of 8–11% of total phenolics, flavonoids and tannins content when compared to extracts performed at 0.1 MPa. Analysis of variance indicated a high goodness of fit of the models used and the adequacy of response surface methodology for optimizing high pressure extraction.
Extracts from fruit processing by-products usually present high amounts of bioactive compounds with several important activities such as antioxidant and antimicrobial capacities. In this work we ...studied (i) the cytotoxicity profile of pomegranate peel extract and (ii) safety and quality aspects after incorporating this extract in carrot juice - a beverage with low antioxidant potential and highly prone to microbial growth. The extract was obtained by high-pressure extraction and was non-cytotoxic towards the Caco-2 cell line after in vitro digestion. The non-cytotoxic pomegranate peel extract was added to carrot juice in a concentration of 5 mg mL-1. Fortified juices were processed by high-pressure and conventional heat and stored under refrigeration. On the 28th day of storage, microbial counts in PPE-fortified juices were reduced by 1.0 log10 CFU mL-1 and the pressurized juices showed significantly fewer counts than the thermal-treated ones. Just after processing, phenolic and flavonoid contents, as well as ABTS and FRAP antioxidant capacities, increased 3.6, 3.5, 8.2, and 9.4-fold, respectively in the fortified juices. The extract addition did not affect any colour parameter and all studied physicochemical parameters i.e. total soluble solids, pH, colour, total phenolics, flavonoids, hydrolysable tannins, and antioxidant capacity remained constant throughout storage. These findings could pave the way towards the development of safe beverages with improved bioactive properties.
Current global research aims to explore the key role of diet and understand the benefits of a balanced diet. Furthermore, many authors have pointed to the added value of by-products as a solution to ...make food production chains more environmentally and economically sustainable. By-products emerge as an alternative matrix to fermentation, and the fermentation process has the potential to transform by-products into value-added products through an efficient and sustainable process. During fermentation, besides the consumption of molecules to grow, microbial enzymes act on several phytochemical compounds, creating new derivative compounds that affect the flavour and function of fermented beverages. As an alternative for consumers with lactose intolerance or vegan or vegetarian diets, new beverages produced from plant by-products and probiotic bacteria hold great promise for the global functional food market. Several challenges were overcome in developing these new products from by-products, namely the availability and quality/standardization of raw materials, adapted microbial starter cultures for fermentation, and optimization of production processes to maximize consumer acceptance and product yield. This review provides an overview of recent research/developments in the field of new fermented beverages from by-products, and aspects related to their functionality, beyond the challenges of these new beverages.
Starch modification arises from the need to obtain starches with the desirable properties, being the physical modification techniques preferred over the chemical ones. Pulsed electric fields (PEF) ...can improve starch extraction and alter starch properties by decreasing the relative crystallinity, gelatinization temperatures and enthalpies, viscosity and pasting temperature. The lamellar repeating distance can be altered depending on the starch botanical origin. PEF can alter the digestible starch content, while maintaining the resistant one. Future research of the amylopectin structure may provide reasoning for these variations in starch digestibility behavior. The in-vitro human simulated digestion points to a decrease in digestibility.
PDF
