A large amount of food wastes and by-products are produced from farm to plate. They represent valuable sources for the production of high-added value compounds such as pectin. Pectin is the ...methylated ester of polygalacturonic acid and presents a wide range of applications in pharmaceutical and cosmetic products as well as in food industry such as gelling agent in fruit-based products, stabilizer in fruit and milk beverages and fruit filling for bakery and confectionary products, among others. Therefore, pectin recovery is of great importance.
The commercially available pectin is almost exclusively derived from citrus peels or apple pomace, by-products from fruit juice manufacturing. But, nowadays the number of novel food waste and by-products sources for pectin extraction are increasing. Moreover, the application of innovative approaches is necessary due to the limitation of conventional processes. The present review will focus on the conventional and innovative processing techniques (microwave extraction, enzymatic extraction, ultrasound-assisted extraction) to extract pectin from different wastes and by-products.
The pectin extraction differs according to the matrix studied as well as temperature, pH, time, solvents, and solid to liquid ratio. The use of innovative extraction processes such as ultrasound, microwave and enzymes can be a useful tool to increase pectin yield and quality, and reducing extraction time, temperature, use of toxic solvents and strong acidic conditions for pectin recovery. Moreover, the combination of solvent modelling and the use of particular extraction processes can enable the selective recovery of pectin.
•Ultrasound, microwave (MW) and enzyme as alternative pectin extraction methods.•Ultrasound can decrease extraction temperature to achieve the maximum pectin yield.•Ultrasound (UAE)+heating reduce pectin extraction time and improve its yield.•Lower extraction time and higher pectin yield after hot-solvent MW extraction.•Enzyme-assisted extraction improves pectin yield compared to untreated samples.
•Pectin extraction from tomato waste was studied.•Ultrasound-assisted extracted pectin was compared to conventional extracted pectin.•Ultrasound treatment significantly shortened extraction time.•1H ...and 13C NMR spectra confirmed the existence of pectin biopolymer structure.•FTIR spectra showed the presence of predominantly esterified pectin form.
Pectin was extracted from tomato waste using two different extraction methods to assess its potential utilization as an alternative source of commercial pectin production. Tomato waste was treated with ammonium oxalate/oxalic acid by conventional extraction (CE), under reflux and ultrasound assisted extraction (UAE) at 37kHz and temperatures of 60°C and 80°C. The pectin obtained from these methods was analysed and compared in terms of yield, chemical properties and structure. Among examined methods, CE at 60°C resulted with the highest yield, but UAE during 15min of sonication produced the pectin of better quality (anhydrouronic acid, methoxy and calcium pectate contents and degree of esterification). NMR and FTIR spectroscopy of isolated pectins revealed predominantly esterified structure, irrespective of extraction conditions. The comparison of the pectin yields obtained after extraction at 80°C, indicate that similar values were found at times of 24h and 15min for CE and UAE, respectively. According to obtained results it can be concluded that main advantage of UAE is considerable shortening of extraction procedure with strong emphasis on environmental friendly processing approach. Therefore, these results suggested that UAE could be used as an efficient technique for the extraction of pectin from tomato waste and by-products.
With the aim of developing a sustainable and efficient extraction of polyphenols-rich fraction from Sorbus spp., Microwave-Assisted Subcritical Water Extraction (MASWE) was selected as the technique ...of choice. Although Sorbus spp. berries are rich in nutraceutical compounds, they are generally underutilised. The extracts obtained contain caffeoylquinic acids (i.e. chlorogenic acids), flavonoids, and organic acids, all of which are active components with potential applications in innovative functional foods due to their potent antioxidant activity. To optimise the extraction protocol, different temperatures and different species of the above genus were studied to improve the recovery of the polyphenolic fractions and obtain products with potential high bioactivity. The best resulting sample was studied more in detail using different colorimetric assays (total content of polyphenols, flavonoids and sugars – TPC, 406.43 mgGAE/gext; TFC, 13.5 mgQE/gext; TSC, 454.1 mgGlu/gext), purification streams, and LC-MS analyses. However, the most remarkable property observed is the outstanding antioxidant activity of the extract (4.74 mmolTrolox.eq/gext). In order to obtain a refined product rich in bioactive compounds, a purification protocol was performed leading to a final TPC selectivity of about 87 % and 10.12 mmolTrolox.eq/gext. Qualitative LC-MS analyses helped to identify chlorogenic acids as predominant in the extract, along with methyl esters of sorbic acid.
The research aims to extract nutrients and bioactive compounds from spirulina using a non-toxic, environmentally friendly and efficient method—Pressurized Liquid Extraction (PLE). In this work, ...Response Surface Methodology (RSM)–Central Composite Design (CCD) was used to evaluate and optimize the extraction time (5–15 min), temperature (20–60 °C) and pH (4–10) during PLE extraction (103.4 bars). The multi-factor optimization results of the RSM-CCD showed that under the pressure of 103.4 bars, the optimal conditions to recover the highest content of bioactive compounds were 10 min, 40 °C and pH 4. Furthermore, the compounds and antioxidant capacity of PLE and non-pressurized extraction extracts were compared. The results showed that under the optimal extraction conditions (10 min, 40 °C and pH 4), PLE significantly improved the antioxidant capacity (2870.5 ± 153.6 µM TE), protein yield (46.8 ± 3.1%), chlorophyll a (1.46 ± 0.04 mg/g), carotenoids (0.12 ± 0.01 mg/g), total polyphenols (11.49 ± 0.04 mg/g) and carbohydrates content (78.42 ± 1.40 mg/g) of the extracts compared with non-pressurized extraction (p < 0.05). The protein molecular distribution of the extracts was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the results showed that there were more small-molecule proteins in PLE extracts. Moreover, Liquid Chromatography Triple Time of Flight Mass Spectrometry (TOF–LC–MS–MS) was used to analyze the phenolic profile of the extracts, and the results showed the extracts were rich on phenolic compounds, such as p-coumaric acid and cinnamic acid being the predominant phenolic compounds in the PLE extract. This indicates that PLE can promote the extraction of bioactive compounds from Spirulina, which is of great significance for the application of PLE technology to obtain active substances from marine algae resources.
Oxidation processes are the major cause of deterioration of meat quality and shelf life of meat products, leading to negative changes in nutritive value and in sensory and physicochemical properties ...of meat. Until now, the synthetic antioxidants like butylated hydroxyl anisole have been commonly used to prevent oxidation, which however may cause potential human health risks and increase toxicity of the product. However, natural antioxidants can be the alternative solution for this problem since plants and plant materials are rich in bioactive compounds (as natural antioxidants) with potential health beneficial effects. Moreover, the interest of consumers in using natural products is still increasing. There is an expectation of replacing synthetic antioxidants and preservatives by natural ones. Therefore, the aim of the present review is to provide information on the effect of natural antioxidants from vegetables and fruits like olives, pomegranate or grapes, and herbs and spices like rosemary, oregano, sage, black cumin or turmeric, rich in bioactive compounds on quality and shelf life of beef and beef products.
The South American plant Stevia rebaudiana Bertoni is a great source of noncaloric sweeteners (steviol glycosides), mainly concentrated in its leaves, but also has important antioxidant compounds ...(vitamin C, polyphenols, chlorophylls, and carotenoids) and other important macro- and micronutrients such as folic acid and all of the essential amino acids except tryptophan. Traditionally, conventional methods have been used to recover nutritionally valuable compounds from plant food matrices. However, nowadays, the need for obtaining greener, sustainable, and viable processes has led both food industries and food scientists to develop new processes in full correspondence with the green extraction concept. This review focuses on some of the most promising nonconventional and emerging technologies, which may constitute a potential alternative to conventional methods or even could be combined to obtain a synergistic effect, thus reducing extraction time as well as solvent consumption and avoiding the use of toxic solvents.
Pomegranate (Punica granatum L.) is well known for its high content of bioactives, including polyphenols, flavonoids, and tannins, which have been shown to exhibit a wide range of biological ...activities, such as antioxidant, antimicrobial, and anticancer effects. It is worth noting that the majority of these molecules are found in the peels, which are usually disposed of after processing, causing a significant amount of waste, amounting to more than 3.6 million t/y. This work investigates microwave-assisted extraction (MAE) in water for the recovery of antioxidants from pomegranate peels (PP), including the optimisation of temperature and extraction times. The total phenolic, anthocyanin, flavonoid, and tannin contents of the recovered extracts were determined, as well as their antioxidant activities, which were found to be 356.35 mgGAE/gExtr, 303.97 µgCy3G/gExtr, 37.28 mgQE/gExtr, 56.48 mgGAE/gExtr, and 5.72 mmolTE/gExtr, respectively (according to the adopted reference). All results were compared with those obtained using a conventional protocol. In addition, the potential for water recycling by means of downstream nanofiltration in optimised MAE was investigated, leading to overall water reuse of approx. 75%. Power consumption (20.92 W/mgGAE) and common green metrics, Reaction Mass Efficiency (RME), E-Factor, and the Process Mass Intensiti/efficiency (PMI, PME), were considered in evaluating the proposed PP valorisation strategy. Finally, the biological activities of the main products were assessed. The antimicrobial properties of the PP extracts against three Gram-positive and three Gram-negative bacteria and their antiproliferative activity towards human cancer cells were tested. S. aureus bacteria was the most susceptible to the PP extracts. All tested products displayed antiproliferative activity against HeLa cells when higher concentrations were tested, with D-PP/NF (obtained from dried PP and sequential nanofiltration) being the most effective. This result was also confirmed via clonogenic analysis, which generally indicated the possible anti-cancer activity of pomegranate peel extracts obtained using this green approach.
Ultrasound treatment is an alternative affordable, effective and reproducible method for the improved recovery of bioactive compounds from various processing streams. The objective of this review is ...to discuss the impact of ultrasound-assisted extraction on the recovery of polyphenols, carotenoids and chlorophylls from vegetal and algae matters. Optimization strategies will need to focus on appropriate equipment design and configuration of ultrasonic components, and extrinsic and intrinsic control parameters including ultrasonic power, temperature and extraction time to maximize the yield and biological activity of the extract. Modeling strategies to characterize and optimize ultrasound processes are also be highlighted in the manuscript.
•UAE is a potential tool for the recovery of antioxidant compounds from vegetal and algae matters.•The effects of UAE differ according to the vegetal matrix.•UAE processing conditions should be optimized for each matrix.•Modeling approaches to optimize UAE were described.
Over the last years, consumers are increasingly demanding for nutritious, healthy and fresh-like food products, with high organoleptic quality. Nowadays, emerging non-thermal technologies have raised ...great interest as a viable alternative to the conventional thermal methods, since they have minimal impact on sensorial and nutritional properties of fresh foods. Ultrasound (US) is one of these promising non-conventional processing technologies and it is especially suitable for preservation of fluid foods. US may be used alone or in combination with other preservation techniques, such as mild heat temperatures, high pressures and antimicrobials. Besides, data on inactivation of food microorganisms by US alone are scarce, because the effects of US are usually not severe enough for a sufficient lethal effect. Since many studies on this subject have been published in the last two decades, this review intends to analyze the main effects of US on microbiological, nutritional and physicochemical parameters of fluid foods. While some general trends can be observed, the effects of US are usually highly variable, not only according to treatment duration and intensity, but also according to the food matrix, suggesting that each matrix should be studied and evaluated separately. Generally, the impact of US on food matrices is minimal, unless longer treatment times and higher amplitudes are applied. Other parameters such as the specific resistance of the microbial strain play also a role.
•The impact of US on physicochemical and nutritional properties is minimal.•Longer treatment times and higher amplitudes induce partial loss.•US effects depend on the specific resistance of the microbial strain and the food matrix.•US combined with other technologies may be a useful tool to preserve liquid foods.•Conditions of US treatment must be optimized for each product separately.
In this study, high hydrostatic pressure extraction (HHPE) and ultrasound-assisted extraction (UAE) were used for the improvement of pectin and polyphenol recovery from tomato peel waste.
HHPE ...enhanced pectin recovery by 15% after 45 min of recycling, in comparison with the conventional extraction (CE) for 180 min. Similar mass fractions of anhydrouronic acid, total sugars and total phenols were obtained by using both methods. FTIR and 1H NMR data confirmed that chemical composition of pectin obtained by HHPE and CE is identical, therefore it was concluded that the faster HHPE method can be used for its further isolation.
Although depectinized residues subjected to UAE in 70% ethanol for 15 min contained two times lower values of total phenols (1625.7 mg/100 g) than pectinized samples (3643.9 mg/100 g), their quantities are not negligible, considering the fact that they are generated after HHPE. At the end of UAE, the residues were exploited as a source of fatty acids, among which lauric, palmitic and stearic acids are dominant.
In conclusion, by shortening the extraction time using HHPE and UAE, it is possible to efficiently produce two valuable functional ingredients, pectin and polyphenols, and at the same time to reduce peel waste from tomato canning industry, which presents an environmental problem.
Utilizing HHPE and UAE as novel and emerging technologies, and combining them with traditional ones (Soxhlet) is given the solution for sequential isolation of pectin, polyphenols and fatty acids from tomato peel waste, generated by canning factory.
Shortening of extraction time using HHPE and UAE, it is possible to replace the conventional techniques, and achieve efficient production of pectin and polyphenols.
Overall, the extraction methodology proposed in this work could provide two valuable benefits, i.e. the producers could find mode for decreasing of disposal costs of waste and consumer would take opportunity that isolated compounds could be reintroduced into food.
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•Tomato peel waste is utilized for sequential extraction of pectin and polyphenols.•Shortening of time using HHPE and UAE is achieved their efficient production.•HHPE enhanced pectin recovery by 15% after 45 min of recycling.•UAE of depectinized samples for 15 min yielded high quantities of phenols.•At the end of sonication, the residues are utilized as a source of fatty acids.
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