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.
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.
•Wine lees anthocyanins were successfully extracted with DES.•DES proved to be more effective extraction solvent compared to acidified ethanol.•DES coupled with ultrasound extraction method was ...successfully applied.•Extraction optimization was conducted by response surface methodology.•Green and efficient extraction of wine lees anthocyanins was proposed.
To establish environmentally friendly extraction methods for the anthocyanins in wine lees, natural deep eutectic solvents (NADES) were investigated as a green alternative to conventional solvents, coupled with high-efficiency ultrasound-assisted extraction. Screening for the optimal NADES for this extraction was initially performed. A choline–chloride-based NADES with malic acid as the hydrogen bond donor was selected as the most promising, which provided more effective extraction of wine lees anthocyanins compared to a conventional solvent. To optimise this extraction of wine lees anthocyanins using the NADES and ultrasound-assisted extraction, response surface methodology was successfully applied. Considering the maximum amount of extracted compounds, the optimal conditions were: extraction time, 30.6min; ultrasound power, 341.5W; and water content in NADES, 35.4% (w/w). This approach using NADES as a green solvent and ultrasound as an alternative energy source represents a good choice for designing eco-friendly extraction methods for phenolic compounds from various sources.
The goal of this review is to provide an overview of the current findings on the major carotenoids and their content in pumpkin products and by-products. The content of total carotenoids and the ...composition of carotenoids in pumpkins depend mainly on the species and cultivar, pedoclimatic conditions, the part of the plant (pulp, peel or seed), extraction procedures and the type of solvent used for extraction. The major carotenoids identified in pumpkins were β-carotene, α-carotene, lutein and zeaxanthin. β-Carotene is the major carotenoid in most pumpkin species. The number and content of total carotenoids are higher when minor carotenoids and ester forms are considered. The use of carotenoids in the development of functional foods has been the topic of many versatile studies in recent years, as they add significant value to foods associated with numerous health benefits. In view of this, pumpkin and pumpkin by-products can serve as a valuable source of carotenoids.
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.
Chamomile (
L.) dried flowers contain a group of interesting biologically active compounds such as sesquiterpenes, flavonoids, coumarins, vitamins, phenolic acids and glucosides. Therefore, the aim ...of the present study was to characterize the composition in bioactive compounds (specialized metabolites) present in water and ethanol extracts of chamomile flowers, together with monitoring the impact of different extraction techniques (conventional vs. ultrasound-assisted extraction (UAE)) on the parameters under investigation. UAE treatment significantly decreased the extraction time of bioactive compounds from herbal material. Polyphenolic compounds content and antioxidant capacity were significantly higher in UAE extracts. Moreover, solvent type had a significant impact on the specialized metabolites content, while the highest vitamin C and polyphenols content were recorded in 50% ethanol (
/
) extracts. Optimization of basic extraction factors: solvent type, temperature and technique is crucial for obtaining the extracts with the highest content of specialized metabolites and antioxidant capacity.
The application of high power ultrasound combined with a slightly increased temperature on raw cow's milk, skimmed cow's milk and skimmed cow's milk that passed the bactofugation process was ...analysed. We combined ultrasound with bactofugation of milk to achieve the microbiological accuracy that is equivalent to pasteurization.
The milk samples (200 mL) were treated for 2.5, 5, 7.5 and 10 min with high-power ultrasound (200 and 400 W) with a frequency of 24 kHz. The treatments were conducted with a constant duty cycle of 100%. Temperatures during the treatments were 20 and 55 °C. The somatic cell count of the aerobic mesophilic bacteria, as well the number of
and
cells were analysed.
From the perspective of the reduction of the total count of bacteria, the best result was achieved by high-power ultrasound at 400 W treated for 10 min. High reduction of
,
and
cells was achieved with ultrasound treatment of raw, skimmed and skimmed cow's milk that passed the bactofugation with a power of 200 and 400 W regardless of the treatment time.
This work combines bactofugation and high-power ultrasound for the inactivation of microoganisms. This combination was used at a slightly increased temperature (up to 55 °C), which is much more economical than pasteurization, while it preserves the sensory and physicochemical properties of milk.
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