Impact of thermal processing and storage temperature on the phenolic profile and antioxidant activity of different varieties of lychee juice

Effects of an inoculation dose of Issatchenkia terricola WJL-G4 on physicochemical properties, active substances, and antioxidant capacity of black, red, and white currant juice

BACKGROUND

Due to the high level of organic acids - primarily citric acid - black, red, and white currants have an excessively sour taste, making taste adjustment during processing challenging. This study investigated and evaluated the effects of an inoculation dose of the acid-reducing yeast Issatchenkia terricola WJL-G4 on several aspect such as physicochemical properties, chromaticity, active substances, and antioxidant capacity. A sensory evaluation was also conducted.

RESULTS

The results indicated that, when the inoculation dose increased from 2% to 12%, the total phenol, total flavonoid, and total anthocyanin content, and antioxidant capacity in currant juice decreased. A low inoculation dose (2-4%) was beneficial for preserving the total phenol and total flavonoid content. Although the levels of most phenolic compounds decreased, the concentrations of caffeic acid, p-coumaric acid, ferulic acid, rutin, and epicatechin were significantly higher than the control after fermentation. Overall acceptability and taste scores of fermented currants improved compared with those of the control group.

CONCLUSION

This experiment provided an effective solution, with a theoretical basis, to the problems of the sour taste and harsh flavor of currant juice. © 2024 Society of Chemical Industry.

Changes in phenolic compounds of Phyllanthus emblica juice during different storage temperature and pH conditions

The aim of this experiment was to investigate the effect of storage temperature and pH on phenolic compounds of Phyllanthus emblica juice. Juice was stored at different temperatures and pH for 15 days and sampled on 2-day intervals. The browning index (BI, ABS420 nm), pH, centrifugal precipitation rate (CPR), and phenolic compounds were evaluated. The results showed 4°C and pH 2.5 could effectively inhibit browning and slow down pH drop of P. emblica juice. The result of orthogonal partial least square-discriminant analysis showed P. emblica juice stored at 4°C and pH 2.5 still had a similar phenolic composition, but at 20°C, 37°C, and pH 3.5, the score plots were concentrated only in the first 3 days. Additionally, gallic acid (GA) and ellagic acid (EA) were screened out to be the differential compounds for browning of P. emblica juice. The contents of GA, epigallocatechin (EGC), corilagin (CL), gallocatechin gallate (GCG), chebulagic acid (CA), 1,2,3,4,6-O-galloyl-d-glucose (PGG), and EA were more stable at 4°C and pH 2.5. Overall, during storage at 4°C and pH 2.5, it could inhibit the increase of GA and EA and decrease of CL, GCG, CA, and PGG, whereas EGC did not show significant difference between storage conditions. The CPR was higher at 4°C, while pH 2.5 could reduce the CPR. In conclusion, in order to maintain stability of phenolic compounds and extended storage period, the P. emblica juice could be stored at low temperature and adjust the pH to increase the stability of juice system.

Unveiling biotransformation of free flavonoids into phenolic acids and Chromones alongside dynamic migration of bound Phenolics in Lactobacillus-fermented lychee pulp

Lactobacillus strains have emerged as promising probiotics for enhancing the bioactivities of plant-based foods associated with flavonoid biotransformation. Employing microbial fermentation and mass spectrometry, we explored flavonoid metabolism in lychee pulp fermented separately by Lactiplantibacillus plantarum and Limosilactobacillus fermentum. Two novel metabolites, 3,5,7-trihydroxychromone and catechol, were exclusively identified in L. plantarum-fermented pulp. Concomitant with consumption of catechin and quercetin glycosides, dihydroquercetin glycosides, 2,4-dihydroxybenzoic acid and p-hydroxyphenyllactic acid were synthesized by two strains through hydrogenation and fission of C-ring. Quantitative analysis revealed that bound phenolics were primarily located in water-insoluble polysaccharides in lychee pulp. Quercetin 3-O-rutinoside was partially liberated from water-insoluble polysaccharides and migrated to water-soluble polysaccharides during fermentation. Meanwhile, substantial accumulations in short-chain fatty acids (increased 1.45 to 3.08-fold) and viable strains (increased by 1.97 to 2.00 Log10 CFU/mL) were observed in fermentative pulp. These findings provide broader insight into microbial biotransformation of phenolics and possible guidance for personalized nutrition.

A-type proanthocyanidins: Sources, structure, bioactivity, processing, nutrition, and potential applications

A-type proanthocyanidins (PAs) are a subgroup of PAs that differ from B-type PAs by the presence of an ether bond between two consecutive constitutive units. This additional C-O-C bond gives them a more stable and hydrophobic character. They are of increasing interest due to their potential multiple nutritional effects with low toxicity in food processing and supplement development. They have been identified in several plants. However, the role of A-type PAs, especially their complex polymeric form (degree of polymerization and linkage), has not been specifically discussed and explored. Therefore, recent advances in the physicochemical and structural changes of A-type PAs and their functional properties during extraction, processing, and storing are evaluated. In addition, discussions on the sources, structures, bioactivities, potential applications in the food industry, and future research trends of their derivatives are highlighted. Litchis, cranberries, avocados, and persimmons are all favorable plant sources. Α-type PAs contribute directly or indirectly to human nutrition via the regulation of different degrees of polymerization and bonding types. Thermal processing could have a negative impact on the amount and structure of A-type PAs in the food matrix. More attention should be focused on nonthermal technologies that could better preserve their architecture and structure. The diversity and complexity of these compounds, as well as the difficulty in isolating and purifying natural A-type PAs, remain obstacles to their further applications. A-type PAs have received widespread acceptance and attention in the food industry but have not yet achieved their maximum potential for the future of food. Further research and development are therefore needed.

Newly formed phenolics selectively bound to the graded polysaccharides of lychee pulp during heat pump drying using UPLC-ESI-QqQ-TOF-MS/MS

Our study investigated heat pump drying (HPD) effects on phenolic-polysaccharide adducts of three lychee pulp grades, their composition and bound phenolic contents. During HPD, the hexose content in water soluble polysaccharide (WSP) increased continuously, and the pentose and glucuronic acid contents in WSP and dilute alkali soluble pectin (ASP) together with the hexose content in ASP increased initially and then decreased due to polysaccharide hydrolases pectinase, polygalacturonase and cellulase. After HPD, the bound phenolic content in WSP, ASP and water unextractable polysaccharide (WUP) significantly increased. Protocatechualdehyde and 3,4-dihydroxybenzeneacetic acid were newly generated phenolics and the former combined with all the three polysaccharide grades, while the latter selectively combined with only WSP. During HPD, WSP and ASP surface structures were gradually broken and became loose, but WUP surface structure was a complete and rough sheet structure. Alkaline hydrolysis caused sparser, more porous surfaces of the three polysaccharide grades. The polyphenol selectivity could be related to substrate selectivity of endogenous oxidases and the type of phenolic compounds.

Magnetic nanometer combined with microwave: Novel rapid thawing promotes phenolics release in frozen-storage lychee

Magnetic nanometer combined with microwave thawing (MN-MT) could become a novel solution to challenges uneven and overheating of microwave thawing (MT), while retaining high thawing efficiency, compared to conventional water immersion thawing (WT). In this study, MN-MT was applied to thaw fruit (lychee as an example) for the first time, and was evaluated by comparison with WT, MT and water immersion combined with microwave thawing (WI-MT). Results showed that MN-MT could significantly shorten the thawing time of frozen lychee by 80.67%, 25.86% and 18.83% compared to WT, MT and WI-MT, respectively. Compared to WT, MN-MT was the only thawing treatment which significantly enhanced the release of quercetin-3-O-rutinose-7-O-α-l-rhamnoside, according to HPLC-DAD. Meanwhile, thermal-sensitive procyanidin B2, phenylpropionic acid and protocatechuic acid were found to be protected from degradations only by MN-MT based on UPLC-ESI-QTOF-MS/MS results. In summary, MN-MT is a potential novel treatment for rapid thawing and quality maintenance of frozen fruits.

Processing of verjuice by ultrasound-assisted microwave heating: An assessment on the enzyme activity retention, technological parameters, and bioactive properties

The present study evaluated the effect of ultrasonication prior to microwave heating applied at 60 °C, 70 °C, and 80 °C on the quality characteristics of verjuice. The sole microwave heating and conventional heating were also performed at the same temperature levels, and effectiveness of three different treatments were evaluated. The required treatment times were decided based on obtaining <10% pectin methylesterase (PME) activity, and ultrasound pretreatment provided the least heating durations. Turbidity, browning index, and viscosity values increased by 3.4 to 14.8-fold, 0.24 to 1.26-fold, and 9.2% to 48.0%, respectively, after all thermal treatments, while Brix values decreased by 1.4% to 15.7%. Ultrasound pretreatment revealed relatively lower browning index in all temperature levels, and almost the highest viscosity values were obtained in sonication pretreated microwave heating as compared with sole microwave and conventional heating. The minimum turbidity value (0.035) was determined in ultrasound-assisted microwave heating at 60 °C. The highest antioxidant capacity (DPPH and ABTS) values were achieved by ultrasound-assisted microwave heating (up to 4.96 and 28.4 mmol Trolox equivalent (TE)/kg, respectively) followed by microwave heating (up to 4.30 and 27.0 mmol TE/kg) and conventional heating (up to 3.72 and 26.8 mmol TE/kg). Furthermore, ultrasonication resulted in better retentions of PME residual activity during 60 days of refrigerated storage (4 °C). Ultrasound pretreatment prior to microwave heating could be a convenient approach for juice processing by reducing the required treatment time and by conserving the quality parameters.

Hydrothermal treatment improves xanthine oxidase inhibitory activity and affects the polyphenol profile of Flos Sophorae Immaturus

BACKGROUND

Flos Sophorae Immaturus (FSI) is rich in polyphenols and a potential uric acid-lowering food. However, the processing of FSI is greatly restricted due to the heat sensitivity and low solubility of polyphenols. In this study, hydrothermal treatment - an effective strategy - was applied to FSI processing. The variation of xanthine oxidase (XO) inhibitory effect and polyphenol composition of FSI during hydrothermal treatment were recorded.

RESULTS

The XO inhibition rate of FSI increased from 32.42% to 89.00% after hydrothermal treatment at 220 °C for 30 min, as well as total polyphenols (from 0.66 to 1.11 mg mL^-1 ) and flavonoids (from 1.21 to 1.58 mg mL^-1 ). However, high thermal temperature (>160 °C) and extended thermal time (>90 min) caused the degradation of polyphenols. Rutin, kaempferol-3-O-rutinoside and narcissoside rapidly degraded and converted to quercetin, kaempferol and isorhamnetin when the temperature exceeded 160 °C. The maximum yields of quercetin, kaempferol and isorhamnetin were at 220 °C for 30 min, 90 min and 90 min, respectively. Meanwhile, the conversion kinetics conformed to the first-order model. Interestingly, these newly formed polyphenols possessed better XO inhibitory effects than their derivatives with 3-O-rutinoside.

CONCLUSION

Polyphenol conversion during hydrothermal treatment was the main reason for enhancing XO inhibitory activity. Therefore, hydrothermal treatment is an appropriate method for improving the XO inhibitory effect of FSI. © 2022 Society of Chemical Industry.

Optimization of Major Extraction Variables to Improve Recovery of Anthocyanins from Elderberry by Response Surface Methodology

Elderberry, which is well known for its richness in anthocyanin, is attracting attention in the bioindustry as a functional material with high antioxidant capacity. The aim of this study is to optimize extraction conditions to more effectively recover anthocyanins from elderberry. In a fundamental experiment to determine the suitable solvent, various GRAS reagents, such as acetone, ethanol, ethyl acetate, hexane, and isopropyl alcohol, were used, and total phenol and anthocyanin contents were detected as 9.0 mg/g-biomass and 5.1 mg/g-biomass, respectively, only in the extraction using ethanol. Therefore, ethanol was selected as the extraction solvent, and an experimental design was performed to derive a response surface model with temperature, time, and EtOH concentration as the main variables. The optimal conditions for maximal anthocyanin recovery were determined to be 20.0 °C, 15.0 min, and 40.9% ethanol, and the total anthocyanin content was 21.0 mg/g-biomass. In addition, the total phenol and flavonoid contents were detected as 67.4 mg/g-biomass and 43.8 mg/g-biomass, respectively. The very simple and economical extraction conditions suggested in this study contributed to improving the utilization potential of anthocyanin, a useful antioxidant derived from elderberry.

A Chemometric Investigation on the Functional Potential in High Power Ultrasound (HPU) Processed Strawberry Juice Made from Fruits Harvested at two Stages of Ripeness

This work aimed to investigate the influence of high-power ultrasound (HPU) technology on the stability of bioactive compounds in strawberry juices obtained from fruits with different stages of ripeness (75% vs. 100%) and stored at 4 °C for 7 days. HPU parameters were amplitude (25, 50, 75, and 100%), pulses (50 vs. 100%) and treatment time (5 vs. 10 min). Amplitude and pulse had a significant effect (p ≤ 0.05) on all bioactive compounds except flavonols and hydroxycinnamic acids. The treatment duration of 5 min vs. 10 min had a significant positive impact on the content of anthocyanins, flavonols and condensed tannins, while the opposite was observed for total phenols, whereas no statistically significant effect was observed for hydroxycinnamic acids. The temperature changes during HPU treatment correlated positively with almost all HPU treatment parameters (amplitude, pulse, energy, power, frequency). Optimal parameters of HPU were obtained for temperature changes, where the highest content of a particular group of bioactive compounds was obtained. Results showed that by combining fruits with a certain ripeness and optimal HPU treatment, it would be possible to produce juices with highly preserved bioactive compounds, while HPU technology has prospects for application in functional food products.

Vacuum Concentration Improves the Quality and Antioxidant Capacity of Pear Paste

A vacuum concentration method was established to produce pear paste using fresh pear juice in this study. The optimal condition was determined by comparing the quality indexes, contents of total phenol and flavonoid, and antioxidant properties of the pear paste produced by traditional heating concentration and vacuum concentration. Electronic nose and electronic tongue were introduced in this study to provide digital smell and taste indicators. The results showed that the best vacuum concentration temperature was 65°C, which led to the best sensory evaluation score and pear paste quality. The browning degree and soluble quinones were the lowest in all tested temperatures, and the content were 60.12% and 72.88% compared with the heating method, respectively. While the values were 148.29%, 209.44%, 310.86%, 120.37%, 106.24%, and 181.26% of total phenol, total flavonoid, vitamin C, 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (·OH) radical scavenging rates, and total reducing power, respectively. The electronic nose could effectively distinguish the vacuum-concentrated pear paste from the traditional heating-concentration pear paste and could provide quality guidance on their flavor differences through characteristic sensors. The electronic tongue tests showed that the vacuum-concentrated pear paste had larger freshness and richness kurtosis. The pear paste made by the optimized vacuum concentration method had higher retention of nutritional and functional components and higher antioxidant capacity, which could be clearly differentiated from the traditional process, thus this method had an applicable potential.

Physicochemical Characterization of Texture-Modified Pumpkin by Vacuum Enzyme Impregnation: Textural, Chemical, and Image Analysis

Texture-modified pumpkin was developed by using vacuum enzyme impregnation to soften texture to tolerable limits for the elderly population with swallowing and chewing difficulties. The impregnation process and macrostructural and microstructural enzyme action were explored by the laser light backscattering imaging technique and a microscopic study by digital image analysis. Texture was analyzed by a compression assay. The effect of enzyme treatment on antioxidant capacity and sugar content was evaluated and compared to the traditional cooking effect. Image analysis data demonstrated the effectiveness of the impregnation process and enzyme action on plant cell walls. Enzyme-treated samples at the end of the process had lower stiffness values with no fracture point, significantly greater antioxidant capacity and significantly lower total and reducing sugars contents than traditionally cooked pumpkins. The results herein obtained demonstrate the capability of using vacuum impregnation treatment with enzymes to soften pumpkins and their positive effects on antioxidant capacity and sugar content to develop safe and sensory-accepted texture-modified products for specific elderly populations.

Lesser-Consumed Tropical Fruits and Their by-Products: Phytochemical Content and Their Antioxidant and Anti-Inflammatory Potential

Açaí, lychee, mamey, passion fruit and jackfruit are some lesser-consumed tropical fruits due to their low commercial production. In 2018, approximately 6.8 million tons of these fruits were harvested, representing about 6.35% of the total world production of tropical fruits. The present work reviews the nutritional content, profile of bioactive compounds, antioxidant and anti-inflammatory capacity of these fruits and their by-products, and their ability to modulate oxidative stress due to the content of phenolic compounds, carotenoids and dietary fiber. Açaí pulp is an excellent source of anthocyanins (587 mg cyanidin-3-glucoside equivalents/100 g dry weight, dw), mamey pulp is rich in carotenoids (36.12 mg β-carotene/100 g fresh weight, fw), passion fruit peel is rich in dietary fiber (61.16 g/100 dw). At the same time, jackfruit contains unique compounds such as moracin C, artocarpesin, norartocarpetin and oxyresveratrol. These molecules play an important role in the regulation of inflammation via activation of mitogen-activated protein kinases (including p38, ERK and JNK) and nuclear factor κB pathways. The properties of the bioactive compounds found in these fruits make them a good source for use as food ingredients for nutritional purposes or alternative therapies. Research is needed to confirm their health benefits that can increase their marketability, which can benefit the primary producers, processing industries (particularly smaller ones) and the final consumer, while an integral use of their by-products will allow their incorporation into the circular bioeconomy.

Athermal Concentration of Blueberry Juice by Forward Osmosis: Food Additives as Draw Solution

This study is to evaluate the athermal forward osmosis (FO) concentration process of blueberry juice using food additives as a draw solution (DS). The effects of food additives, including citric acid, sodium benzoate, and potassium sorbate, on the concentration processes are studied, and their effects on the products and membranes are compared. Results show that all these three food additives can be alternative DSs in concentration, among which citric acid shows the best performance. The total anthocyanin content (TAC) of blueberry juice concentrated by citric acid, sodium benzoate, and potassium sorbate were 752.56 ± 29.04, 716.10 ± 30.80, and 735.31 ± 24.92 mg·L^-1, respectively, increased by 25.5%, 17.8%, and 19.9%. Meanwhile, the total phenolic content (TPC) increased by 21.0%, 10.6%, and 16.6%, respectively. Citric acid, sodium benzoate, and potassium sorbate all might reverse into the concentrated juice in amounts of 3.083 ± 0.477, 1.497 ± 0.008, and 0.869 ± 0.003 g/kg, respectively. These reversed food additives can make the TPC and TAC in juice steadier during its concentration and storage. Accordingly, food additives can be an excellent choice for DSs in the FO concentration process of juices, not only improving the concentration efficiency but also increasing the stability of blueberry juice.

Effect of food processing on antioxidants, their bioavailability and potential relevance to human health

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Processing alters the amount, matrix interaction, and structure of antioxidants.

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It is not easy to dissociate processing effects from food matrix effects.

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It is still difficult to make general statements on the effects of processing on bioavailability.

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Facilitated release by heat, pressure, etc. contributes to increased bioaccessibility.

It has long been recognized that the antioxidants present in fresh plant materials may be very different to those we ingest via our foods. This is often due to the use of food processing strategies involving thermal/non-thermal treatments. Current research mostly focuses on determining what is present in vegetative starting materials; how this is altered during processing; how this influences activity in the gut and following uptake into bloodstream; and which in vivo physiological effects this may have on human body. Having a better understanding of these different steps and their importance in a health-and-nutrition-context will place us in a better position to breed for improved crop varieties and to advise the food industry on how to optimize processing strategies to enhance biochemical composition of processed foods. This review provides an overview of what is currently known about the influence which food processing treatments can have on antioxidants and gives some pointers as to their potential relevance.

Newly generated and increased bound phenolic in lychee pulp during heat-pump drying detected by UPLC-ESI-triple-TOF-MS/MS

BACKGROUND

During the thermal processing of fruit, it has been observed for phenolic compounds to either degrade, polymerize, or transfer into macromolecules. In this study, the bound and free phenolic compound composition, content, and phenolic-related enzyme activity of lychee pulp were investigated to determine whether the free phenolic had converted to bound phenolic during heat-pump drying (HPD).

RESULTS

It was found that after HPD, when compared with the fresh lychee pulp (control), the content of bound phenolics of dried lychee pulp had increased by 62.69%, whereas the content of free phenolics of dried lychee pulp decreased by 22.26%. It was also found that the antioxidant activity of bound phenolics had also increased after drying. With the use of high-performance liquid chromatography-tandem mass spectrometry, it was identified that (+)-gallocatechin, protocatechuic aldehyde, isorhamnetin-3-O-rutoside, 3,4-dihydroxybenzeneacetic acid, and 4-hydroxybenzoic acid were newly generated during HPD, when compared with the control sample. After drying, the contents of gallic acid, catechin, 4-hydroxybenzoic acid, vanillin, syringic acid, and quercetin in bound phenolics had also increased, and polyphenol oxidase and peroxidase still showed enzyme activity, which could be related to the conversion of free phenolics to bound phenolics.

CONCLUSION

Overall, during the thermal processing of lychee pulp, the free phenolics weres found to be converted into bound phenolics, new substances were generated, and antioxidant activity was increased. Hence, it was concluded that HPD improved the bound phenolics content of lychee pulp, thus providing theoretical support for the lychee processing industry. © 2021 Society of Chemical Industry.

Innovative and Sustainable Technologies to Enhance the Oxidative Stability of Vegetable Oils

To meet consumers’ demand for natural foods, edible oil producers and food processing industries are searching for alternatives to synthetic antioxidants to protect oils against oxidation. Antioxidant compounds extracted from different plant parts (e.g., flowers, leaves, roots, and seeds) or sourced from agri-food industries, including residues left after food processing, attract consumers for their health properties and natural origins. This review, starting from a literature research analysis, highlights the role of natural antioxidants in the protection of edible oils against oxidation, with an emphasis on the emerging and sustainable strategies to preserve oils against oxidative damage. Sustainability and health are the main concerns of food processing industries. In this context, the aim of this review is to highlight the emerging strategies for the enrichment of edible oils with biomolecules or extracts recovered from plant sources. The use of extracts obtained from vegetable wastes and by-products and the blending with oils extracted from various oil-bearing seeds is also pointed out as a sustainable approach. The safety concerns linked to the use of natural antioxidants for human health are also discussed. This review, using a multidisciplinary approach, provides an updated overview of the chemical, technological, sustainability, and safety aspects linked to oil protection.

Evolution of antioxidant properties of orange beverage during storage: Effects of time and temperature

Fruit beverages are the most consumed refreshing products worldwide. The quality of these drinks is not only influenced by the initial composition of the product but also by conditions and duration of storage. The purpose of the present investigation was to evaluate the incidence of two conservation parameters (temperature and time) on some bioactive compounds (phenolic, flavonoid, and carotenoid contents) and antioxidant capacity, measured by free radical scavenging activity (RSA) and ferric reducing power (FRP), on orange beverage during storage. The industrial drinking product freshly procured were subjected to storage under variable temperatures (5, 25, 35, and 45 °C) then analyses of bioactive compounds contents and antioxidant activity were performed periodically (0, 10, 20, and 30 days). The results showed that the initial orange beverage was endowed with interesting phenolic compound contents and considerable antioxidant potential. In the exception of 5 °C, which provided steady antioxidant parameters, all other temperatures induced decreases of analyzed phytochemicals and antioxidant activities proportionally with raising of storage temperature. The duration of storage for the temperatures 25, 35, and 45 °C also affected negatively antioxidant parameters in a proportional manner to time. The orange beverage was an interesting natural source of bioactive compounds but the duration of storage in relation to temperature must be chosen properly.

Effect of Issatchenkia terricola WJL-G4 on Deacidification Characteristics and Antioxidant Activities of Red Raspberry Wine Processing

Our previous study isolated a novel Issatchenkia terricola WJL-G4, which exhibited a potent capability of reducing citric acid. In the current study, I. terricola WJL-G4 was applied to decrease the content of citric acid in red raspberry juice, followed by the red raspberry wine preparation by Saccharomyces cerevisiae fermentation, aiming to investigate the influence of I. terricola WJL-G4 on the physicochemical properties, organic acids, phenolic compounds and antioxidant activities during red raspberry wine processing. The results showed that after being treated with I. terricola WJL-G4, the citric acid contents in red raspberry juice decreased from 19.14 ± 0.09 to 6.62 ± 0.14 g/L, which was further declined to 5.59 ± 0.22 g/L after S. cerevisiae fermentation. Parameters related to CIELab color space, including L*, a*, b*, h°, and ∆E* exhibited the highest levels in samples after I. terricola WJL-G4 fermentation. Compared to the red raspberry wine pretreated without deacidification (RJO-SC), wine pretreated by I. terricola WJL-G4 (RJIT-SC) exhibited significantly decreased contents of gallic acid, cryptochlorogenic acid, and arbutin, while significantly increased contents of caffeic acid, sinapic acid, raspberry ketone, quercitrin, quercetin, baicalein, and rutin. Furthermore, the antioxidant activities including DPPH· and ABTS+· radical scavenging were enhanced in RJIT-SC group as compared to RJO-SC. This work revealed that I. terricola WJL-G4 had a great potential in red raspberry wine fermentation.

Innovative Technologies for Extraction and Microencapsulation of Bioactives from Plant-Based Food Waste and their Applications in Functional Food Development

The by-products generated from the processing of fruits and vegetables (F&V) largely are underutilized and discarded as organic waste. These organic wastes that include seeds, pulp, skin, rinds, etc., are potential sources of bioactive compounds that have health imparting benefits. The recovery of bioactive compounds from agro-waste by recycling them to generate functional food products is of increasing interest. However, the sensitivity of these compounds to external factors restricts their utility and bioavailability. In this regard, the current review analyses various emerging technologies for the extraction of bioactives from organic wastes. The review mainly aims to discuss the basic principle of extraction for extraction techniques viz. supercritical fluid extraction, subcritical water extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and pulsed electric field extraction. It provides insights into the strengths of microencapsulation techniques adopted for protecting sensitive compounds. Additionally, it outlines the possible functional food products that could be developed by utilizing components of agricultural by-products. The valorization of wastes can be an effective driver for accomplishing food security goals.

Microencapsulation of Horseradish (Armoracia rusticana L.) Juice Using Spray-Drying

Horseradish contains many bioactive compounds with antioxidant activity. The current study aimed to evaluate the effect of various wall materials and their ratios on the physical properties and bioactive-compound retention and stability in microencapsulated horseradish leaf and root juices. Horseradish juice was microencapsulated using maltodextrin, maltodextrin/gum Arabic, soy protein isolate, and starch with three different core-to-wall ratios. The total phenolic, total flavonoid, total flavan-3-ol, and total phenolic-acid contents, as well as antioxidant activity, were determined using spectrophotometric methods, whereas individual phenol profiles were determined by high-performance liquid chromatography (HPLC). Multivariate analysis of variance showed that plant material, wall material, and core-to-wall ratio had a significant effect on the bioactive-compound retention and antioxidant-activity preservation. Microcapsules produced from horseradish leaf juice had a significantly higher content of phenolic compounds and antioxidant activity compared to root-juice microcapsules. However, better retention was observed for microencapsulated horseradish root juice. Maltodextrin and maltodextrin/gum Arabic were the most effective wall materials for the retention of bioactive compounds, while they also had a smaller particle size and better solubility. The horseradish-juice microcapsules possess a high content of rutin. The highest stability of bioactive compounds after storage was found at a core-to-wall ratio of 20:80.

Comparison of the phenolic profiles and physicochemical properties of different varieties of thermally processed canned lychee pulp

Lychee pulp is rich in phenolics and has a variety of biological activities. However, the changes in the phenolic profile under heat treatment are unknown. The effect of the heat treatment temperature on commercial varieties (Guiwei and Nuomici) of canned lychee was investigated by comparing samples that were either unheated (UH), underwent 70 °C heat treatment (HT70) or underwent 121 °C heat treatment (HT121) and then were stored at room temperature. The results showed that the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the UH, HT70 and HT121 samples were significantly decreased after storage at room temperature for 9 d, 13 d and 25 d, respectively. However, the TPC, TFC and antioxidant activity of HT121 canned lychee were still significantly higher than those of the UH and HT70 samples. However, the texture characteristics of the HT121 samples were worse than those of the UH and HT70 samples, and the color of the canned lychee was darker after the HT121 treatment. Nine individual phenolic compounds were detected in the canned lychee by HPLC-DAD. The gallic acid content was increased after HT121 treatment. In particular, (−)-gallocatechin was generated by HT121 thermal processing. However, after storage at room temperature for 9 d, the contents of (−)-gallocatechin in canned Guiwei and Nuomici were decreased by 96.27% and 94.04%, respectively, and (−)-gallocatechin disappeared after 25 d. In summary, the phenolic contents and antioxidant activity of canned lychee are increased by high-temperature treatment.

Lychee pulp is rich in phenolics and has a variety of biological activities.