Juice Processing Research Articles

Effectiveness assessment of the bifidobacteria encapsulation when enriching juice-containing beverages with probiotics

Beverages are among the most popular types of products that attract attention of researchers for enrichment with functional ingredients. The introduction of probiotics into the food matrix can increase the usefulness of food products, including beverages. However, probiotics are extremely sensitive to extreme environmental conditions, which significantly limits their ability to survive in food. The aim of the research is to establish an effect of encapsulation on the preservation of bifidobacteria in an enriched juice-containing beverage. Capsules from sodium alginate were used to protect probiotic microorganisms (bifidobacteria of six strains in the symbiotic starter) from unfavorable conditions of the environment of the food system and the gastrointestinal tract. The capsules were obtained by the drip method. The stability of the capsules was determined under different conditions. Their solubility in water and at pH values typical for the stomach (1.1–1.6), small intestine (7.8–8.2), and large intestine (8.0–8.5) were studied. The tests were carried out upon keeping in buffer solutions for 15 and 30 min. In addition, the stability of the capsules in apple juice with a pH of 3.82 when stored at 4±1°C for 7, 14, 21, and 28 days was assessed. Capsule losses during heat treatment were analyzed. The amount of bifidobacteria extracted from the capsules after mechanical destruction with their subsequent inoculation on the GMK1 medium was also monitored during juice storage. The results of the studies showed that the greatest destructive effect was observed in an acidic environment typical for the stomach, where losses amounted to 47.4% after 30 min. Capsule losses at pH values typical for different parts of the intestine ranged from 25.3 to 30.9%. The selected food system, apple juice, turned out to be a less aggressive environment for the capsules, in which the destruction of capsules was 8.7% after 28 days of storage. Capsule losses under the selected juice pasteurization modes ranged from 60.17% during processing for 10 minutes at 85°C to 67.42% during juice processing for 30 minutes at 98°C. The differences were statistically significant (p≤0.05). Thus, using the obtained data, it is possible to predict the total loss of capsules and probiotic microorganisms during the digestion and storage of the product and inoculate the required amount to impart probiotic properties to the product. The research has development prospects taking into account the possibility of varying the taste and aroma properties of both the food system and the capsules.

Flavor formation mechanisms based on phospholipid fermentation simulation system in oyster juice co-fermented by Lactiplantibacillus plantarum and Saccharomyces cerevisiae.

Oyster juice was co-fermented with Lactiplantibacillus plantarum 3-B and Saccharomyces cerevisiae 7-C, and the quality of the oyster juice and the relationships between phospholipids and flavor formation were investigated. The olfactory odor intensities of (E,E)-2,4-heptadienal and (E,Z)-2,6-nonadienal, which impart off-flavors, were reduced in the co-fermented oyster juice in comparison with the unfermented juice. Co-fermentation resulted in an increase of 5.34% in docosahexaenoic acid and 20.22% in eicosapentaenoic acid. The flavor formation mechanisms were explored using a phospholipid-based fermentation simulation system. The levels of the differential phospholipids lysophosphatidylcholine 15:0, lysophosphatidylcholine 16:0, and phosphatidylethanolamine 20:0/16:0 in the co-fermented system decreased by 25.13μg/mL, 6.87μg/mL, and 0.30μg/mL, respectively. Hexanal, (E,E)-2,4-heptadienal, and (E)-2-octenal were not detected in the co-fermented system. This study provides a novel approach to the processing of oyster juice and examines the phospholipid-related pathways involved in flavor formation.

Polyphenolic compounds in Sauvignon Blanc - from grapes to wine

At harvest, the metabolic composition of wine grapes reflects the accumulated effect of the environmental conditions, the stresses endured, and viticultural manipulations applied during the growing season. The role of the winemaker is to extract and nurture this “metabolite potential” throughout the winemaking process. However, it is typically difficult to relate this grape potential to that of the eventual wines. In this study, a holistic view of Sauvignon Blanc grape and wine polyphenolic compounds was attempted by measuring these compounds from different matrices, from ripe grape tissues up to the final wine, including the submatrices, such as juice, pomace and sediment. Sauvignon Blanc vines from one vineyard block were manipulated to yield berries with distinctly different phenolic potentials by creating a high light (HL) or a low light (LL) microclimate in the fruiting zone of the canopy during the growing season. The analyses of the HL and LL berries and wines, as well as concomitant analyses of the phenolic compounds in the submatrices, allowed their tracing as they were (i) transferred from one matrix to another, (ii) lost as waste products, or (iii) affected by different winemaking practices (skin contact and/or fermentation in contact with the juice sediment) implemented in the experimental design. In berries, flavonols showed the largest increase due to sun exposure (HL treatment) but were absent from the juice samples at all juice processing stages. They were however detected in the juice sediment, together with high concentrations of organic acids and sugars. Juice processing was noted for dramatic fluctuations in metabolite concentrations suggesting intense metabolic activity in this pre-fermentation matrix. Both skin contact and sediment contact treatments delivered wines with higher concentrations of coutaric acid (the ester formed from coumaric and tartaric acid) and the flavanol catechin while epicatechin concentrations was unaffected. The higher catechin concentrations did not lead to increased perceived bitterness in the wines, except in the sediment contact treatments. The total phenolic compound concentration of wine from LL (low phenolic potential) grapes was comparable to wine from HL (high phenolic potential) grapes, when skin contact, or sediment contact treatments were employed. From a sensory perspective, the sediment contact decreased the fruity aromas of Sauvignon Blanc, while the skin contact treatment enhanced the sensorial properties of the wines made from the LL grapes, allowing increased extraction from the skin-accumulated impact compounds.

Development and Optimization of a Real-Time Monitoring System of Small-Scale Multi-Purpose Juice Extractor.

According to the concept of smart postharvest management, an information and communication technology sensor-based monitoring system is required in the juicing process to reduce losses and improve process efficiency. Such technologies are considered economically burdensome and technically challenging for small-scale enterprises to adopt. From this perspective, this study aimed to develop a smart monitoring system for the juicing processes in small-scale enterprises and to identify the optimal operating conditions based on the monitoring data. The system developed is equipped with two weight sensors attached to the twin-screw juice extractor, allowing for the automatic measurement of the weight of the raw material and the resulting juice product. The measured data are automatically transmitted and stored on a computer. Additionally, the system was designed to remotely control the speeds of the juicing and feeding screws, which are the primary controlling factors of the twin-screw juicer. Juice yield and processing time were optimized using carrots and pears. The optimal juicing and feeding speeds for pear yield were found to be 167.4 rpm and 1557 rpm, respectively; carrots achieved an optimal yield at a juicing speed of 502.2 rpm and feeding speed of 1211 rpm. In contrast, the processing time was minimized at juicing-feeding speeds of 6-6 and 7-5 for pears and carrots, respectively. Consequently, it was challenging to determine the optimal conditions for simultaneously optimizing the yield and processing time. This also suggests that the juicing process is affected by the properties of the fruits and vegetables being processed. By developing a system capable of accumulating the data necessary for the digitization of postharvest management and food processing, this research offers a valuable platform for the smart monitoring and optimization of the juicing process.

Advancing Energy Recovery: Evaluating Torrefaction Temperature Effects on Food Waste Properties from Fruit and Vegetable Processing

Most organic waste from food production is still not used for energy production. From the perspective of energy production, one option is to valorise the properties of organic waste. The fruit juice industry is growing rapidly and generates large amounts of waste. One of the main wastes in food and fruit juice processing is peach pits and apple peels. The aim of this study was to analyse the influence of torrefaction temperature on the properties of food waste, namely apple peels, peach pits and pea shells, in order to improve their energy value and determine their potential for further use and valorisation as a renewable energy source. The aim was to analyse the influence of different torrefaction temperatures on the heating value (HHV), mass yield (MY) and energy yield (EY) in order to better understand the behavior of the thermal properties of individual selected samples. The torrefaction process was carried out at temperatures of 250 °C, 350 °C and 450 °C. The obtained biomass was compared with dried biomass. For apple peels, HHV after torrefaction was (28 kJ/kg), MY decreased by (66–34%), while EY fell by (97–83%). Peach pits, despite a higher HHV after torrefaction (18 kJ/kg), achieved low MY (38–89%) and EY (59–99%), which reduces their efficiency in biochar production. Pea peels had EY (82–97%) and a lower HHV after torrefaction (11 kJ/kg), but their high ash content limits their wider use. The results confirm that, with increasing temperature, MY and EY for all selected biomasses decrease, which is a consequence of the degradation of hemicellulose and cellulose and the loss of volatile compounds. In most cases, increasing the torrefaction temperature improved the resistance to moisture adsorption, as this is related to the thermal process that causes structural changes. The results showed that the torrefaction process improved the hydrophobic properties of the biomass samples. Temperature was seen to have a great impact on mass energy efficiency. Apple peels generally had the highest mass and energy yield.

Processing of fruit juices: Techniques, challenges, and advances

Processing of fruit juices: Techniques, challenges, and advances

Evaluation of integrated polysaccharide, biopolymers and clay composite membranes for clarification process of citrus fruit (sweet lime) juice.

This study focuses on the development of an efficient membrane-based clarification process to enhance the performance of subsequent ultrafiltration and produce high-quality sweet lime juice. A range of casting solutions were prepared using a blend of pore-forming polymers, including polyvinylpyrrolidone (PVP), polyvinylidene fluoride (PVDF), and cellulose acetate (CA), dissolved in dimethylformamide (DMF) solvent through the phase inversion technique. To further enhance the membrane's performance, four biopolymers poly (lactic acid) (PLA), xanthan gum, chitosan, and gelatin were incorporated, with and without clay, to refine its structure, porosity, and surface properties. The resulting membranes were characterized by FT-IR, SEM, and AFM, and their flux behaviour and fouling profiles were evaluated. The quality of the clarified juice was assessed by measuring total suspended solids (TSS), clarity, color, and apparent alcohol insoluble solids (AIS). Despite a reduction in permeate flux, the Xanthan-clay-loaded membrane enhanced juice quality and clarity. For the PLA-based membrane and the xanthan-based membrane, the fouling coefficient was lower. This membrane-based clarification technique can be applied effectively in the juice processing industries to improve product quality.

Evaluating Natural and Treated Clay Coagulants for Wastewater Treatment in Agro-Food Industries Related to Meat, Oil, and Fruit Juice Processing

Evaluating Natural and Treated Clay Coagulants for Wastewater Treatment in Agro-Food Industries Related to Meat, Oil, and Fruit Juice Processing

Detannying in Cashew Apple Juice (Anacardium occidentale L.) by Chemical Agents

Vietnam is the leading exporter of cashew nuts globally; however, the cashew apple, constituting 75% of the total harvest from cashew trees, remains underexploited despite its rich nutrient content. The main reason is that cashew apple contains high amount of tannin which causes astringency. Consequently, this undesired compound poses a significant challenge for food product development. Thus, tannin removal is critical in cashew apple juice processing to improve sensorial characteristic and produce a nutritious beverage from cashew apple. Gelatin, modified cassava starch (MCS), and polyvinyl polypyrolidone (PVPP) are the most recommended agents for tannin reduction. This study evaluated the efficacy of these clarifying agents based on agent concentration, processing time, and juice pH. Results indicated that gelatin at 2 g/L for 30 min at pH 3 reduced tannin by 34.31%; MCS removed 41.34% of tannins at 3 g/L for 30 min at pH 3; and PVPP achieved tannin removal of 32.45% at 4 g/L for 30 min at pH 4. All chemical treatments decreased nutritional values, including vitamin C, sugars, polyphenols, and antioxidant activity. While MCS demonstrated the highest tannin removal efficiency, the sensory quality of the treated juice requires further enhancement due to low pH.

Bactris guineensis, an underutilized Costa Rican palm fruit: juice processing and its nutritional profile

Introduction. Bactris guineensis is a crop that produces visually appealing fruits resembling purple-black grapes with round seeds. This palm species naturally thrives in the lowland regions of tropical America. However, limited information available about this fruit. Objective. To investigate the nutritional composition, bioactive compound content, antioxidant capacity, and aroma profile of the huiscoyol fruit grown in Costa Rica, as well as to evaluate the effects of juice processing (enzymatic maceration and thermal treatment) on its bioactive compounds and antioxidant capacity. Materials and methods. Fruits were collected from randomly selected palms and bunches in Guanacaste Conservation Area, specifically in Palo Verde and Cañas, during peak harvest years (2007, 2011, 2014, and 2016). Nutritional composition, bioactive compound content, antioxidant capacity, and aroma and polyphenol profiles were analyzed. Juices were prepared using thermal treatment, enzymatic maceration, and a combination of both methods. The bioactive compound content and antioxidant capacity were assessed following each treatment. Results. Huiscoyol fruit exhibited high fiber content [7.3 ± 2.5 g per 100 g of fresh weight (fw)], and significant potassium content (307 ± 98 mg per 100 g fw). Anthocyanin levels ranged from 28.3 to 47.9 mg per 100 g fw, with cyanidin-3-O-rutinoside as the predominant compound. Total polyphenol content varied between 219 and 1,013 mg gallic acid equivalents per 100 g fw. Vitamin C content reached a maximum of 48 mg per 100 g fw. Antioxidant capacity, as measured by H-ORAC, ranged from 6,690 to 14,688 μmol Trolox equivalents per 100 g fw. Enzymatic maceration and thermal treatments applied to the juice did not significantly affect the bioactive compounds content or antioxidant activity (p > 0.05). Conclusion. Huiscoyol fruit demonstrate nutritional and antioxidant potential, making it promising ingredient for funtional beverages. Its bioactive components, such as polyphenols and anthocyanins, showed remarkable stability under thermal and enzymatic processing conditions.

Optimization of ultrasound-assisted extraction of mango cotyledon starch: Physicochemical, structural, thermal and functional properties

Mango (Mangifera indica L.) seed, a byproduct of mango pulp and juice processing, is recognized for its abundant starch content. The advancement of the modern food industry has prompted a shift away from traditional starch extraction methods due to their environmental impact and low efficiency. The study aimed to optimize the ultrasound-assisted extraction process of starch from the cotyledons of mango seeds, employing response surface methodology with a customized optimal design and an optimal-I optimality criterion. We investigated the effects of cotyledon/water ratio, time, power, and sonication frequency on maximizing starch extraction yield. We explored the impact of ultrasound on structural, morphological, functional, and pasting properties. The maximum starch extraction yield was 50.74%. This yield was about 82.4% higher than that of conventional wet extraction. Ultrasound-assisted extraction increased starch purity and amylose content; it reduced granule size while enhancing all starch pasting properties without affecting starch's chemical structure and morphological, thermal, and functional properties. The mango cotyledon starch can be classified as medium to normal amylose content starches, exhibiting A-type polymorphs, fast-swelling, and capable of forming strong, firm, low-sticky gels. These results demonstrate the potential applications of mango residue and ultrasound technology in the food and pharmaceutical industry.

Fungi associated with orange juice production and assessment of adhesion ability and resistance to sanitizers.

Orange juice is widely consumed worldwide due to its sensory and nutritional characteristics. This beverage is susceptible to contamination by acidic-tolerant microorganisms due to its low pH, especially filamentous fungi and yeasts. To minimize fungal spoilage, companies usually submit juice to thermal treatments; sanitizers are also applied on surfaces to maintain the microbiological quality. This study aimed to identify potential contamination sources in a juice processing line and to verify the susceptibility of isolated yeasts and filamentous fungi to food-grade sanitizers. Also, their ability to form single and binary adherent cells was assessed. The results revealed the presence of fungi in all samplings performed, with the most prominent microorganisms identified as Paecilomyces variotii, P. paravariotii, Pichia kudriavzevii and Wickerhamomyces anomalus. After obtaining results for sanitizer resistance and adhesion ability of the isolates, these were submitted to multivariate analysis using hierarchical cluster analysis (HCA), and two groups were found: one composed mostly of filamentous fungi (16/18) with low adhesion potential and one group formed by yeasts with high adhesion ability and resistance to sanitizers. Microscopy images corroborate those data, demonstrating the importance of yeast cell agglomerates along germinated spores of filamentous fungi and the importance of adhered biomass to protect cells against the sanitizers tested. This study is the first to combine fungi isolated from a beverage processing line and aims to contribute to the current knowledge of fungal adhesion and sanitizer resistance.

Uncertainty and variability in post-processing kinetic calculations- nutritional quality loss in fruit juice products

During juice processing and subsequent handling, vitamins are prone to degradation. Quantitative assessment of the effect of post-processing parameters on nutrient loss dependent shelf life can be implemented using either typical deterministic kinetic analysis or stochastic approaches, incorporating all identified sources of uncertainty. The presented case study is based on published data of post processing Vitamin C degradation in orange juice, processed via high pressure or thermal pasteurization. Monte Carlo simulations were implemented to account for different types of uncertainty, i.e. cold chain temperature variability, raw material biological variance and parameter uncertainty. Results showed that products, processed thermally or by high pressure, had a shelf life in the 51–70, vs 98–117 days range, respectively, considering all sources of uncertainty. In comparison to the respective single estimates of 60 and 110 days, based on fixed parameter values and constant temperature conditions, the distributions obtained depict more realistically the expected product quality variation.

Recovery of bioactive compounds from pineapple waste through high-pressure technologies

This study aimed to obtain bioactive compounds from the residue from pineapple (Ananas comosus L. Merril) juice processing, using supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE). The SFE were performed using ethanol as a co-solvent and evaluating different pressure, temperature, and co-solvent percentage. For the PLE, temperature and ethanol percentage were assessed. The best extraction conditions for SFE were 20 MPa, 60 °C, and 15 % ethanol, while for PLE they were obtained at 10 MPa, 100 °C with 50 % and 75 % ethanol. Both methods presented a higher concentration of bioactives than other recognized vegetable waste sources. However, it was observed that PLE showed a higher overall extract yield, phenolic compounds, flavonoids, carotenoids, and antioxidant activity. The main phenolic compounds identified were caffeic acid and ferulic acid. Therefore, pineapple residue is a potential source of bioactive compounds, and the pressurized liquid extraction technique proved more efficient for their recovery.

Research on technological process for production of muskmelon juice (Cucumis melo L.)

Abstract The effects of hydrolysis of muskmelon pomace on fruit juice recovery efficiency, transmittance, total phenolic content, total ascorbic acid content, total flavonoid content, and total carotenoid content have been studied. The aim of this study was to evaluate the potential use of pectinase enzyme in the hydrolysis process, specifically looking at the effects of pH, temperature, time, and enzyme concentration on the production of effective muskmelon juice. Additionally, the optimal mixing ratio of ingredients such as melon juice content, Brix level, citric acid, and additives (pectin, sodium carboxymethyl cellulose [CMC], xanthan gum) was investigated to create a high-quality muskmelon juice product. The results showed that using a pectinase enzyme concentration of 0.2%, a pH of 5.0, and a hydrolysis temperature of 45°C for 120 min resulted in a muskmelon juice product with a hydrolyzed juice content of 20%, a Brix level of 12%, and a citric acid addition rate of 0.04%. The addition of xanthan gum at a rate of 0.03% also contributed to the desired flavor and color of the juice. These findings provide valuable insights for the development of effective muskmelon juice processes.

Ozonation as an emerging technique for inactivating microorganisms and mitigating pesticides in apple juice

ABSTRACT Microorganisms and pesticide residues are among the major health concerns associated with food products. Although ozone (O3) is currently being employed in various applications in apple processing, there are few studies investigating the effects of O3 treatments on microorganisms and pesticides in apple juice. The purpose of this study was to investigate the effects of O3 treatment on microorganisms, pesticide residues, and physicochemical properties of apple juice and to compare with that of classical pasteurization. O3 was as effective as pasteurization against E. coli and coliform bacteria; the counts of these microorganisms were below the detectable level after a treatment for 15 min. O3 was also effective in reducing the counts of total aerobic mesophilic bacteria and yeast-mold, but longer treatments were required for total inactivation. All the pesticides investigated were degraded by O3, but at different rates. Reduction rates were quite high (75–100%) for methoxyfenozide, dimethoate, and pyrimethanil, however, acetamiprid and imidacloprid were degraded by only 7.1% and 14.5%, respectively. O3 treatment caused drastic decreases in color and turbidity values, total phenolic content, and antioxidant activity of apple juice. Results revealed that the use of ozone in juice processing has potential as a technological solution to product contamination problem.

Towards the Valorization of Elderberry By-Product: Recovery and Use of Natural Ingredients for Sorbet Formulations

One of the food industry’s greatest challenges is to find natural ingredients capable of conferring antioxidant and color properties. In addition, the agri-food industry generates by-products that are often treated as waste, despite their abundance of phytochemicals that can be recovered and used as food ingredients. This study explores the potential of elderberry pomace, an industrial by-product of juice processing rich in anthocyanins and polyphenols, as a natural food additive in blueberry sorbet. Elderberry pomace was incorporated into the sorbet formulation in powder form or as aqueous extracts at two different concentrations. The analysis of the pomace extract by UHPLC-DAD-MS showed the presence of four anthocyanins: cyanidin-3,5-O-diglucoside, cyanidin-3-O-sambubioside-5-O-glucoside, cyanidin-3-O-sambubioside, and cyanidin-3-O-glucoside. The physicochemical properties of the sorbets such as pH, °Brix, overrun, melting rate, and color were evaluated, as well as their levels of total phenolic compounds, total monomeric anthocyanins, and in vitro antioxidant activity. The potential of sorbets to stimulate the growth of probiotic bacteria was evaluated and a sensory analysis was conducted to assess consumer acceptance. Results indicated that the sorbet containing the more concentrated extract presented higher overrun, faster melting rate, higher contents of phenolic compounds and anthocyanins, and higher antioxidant activity compared to the control. Additionally, this formulation showed a darker hue (lower L* value) and a tendency to stimulate probiotic bacteria. Moreover, the sorbets with pomace in their composition had good consumer acceptability. These findings highlight the potential of elderberry pomace to be used as a natural, sustainable ingredient in the ice cream industry, aligning with growing consumer trends towards healthier and eco-friendly products.

Impact of yeast selection on composition of vinegar fermented from pomace of a Finnish apple cultivar

Alcoholic beverages and vinegar products were produced using the pomace of a Finnish apple cultivar, and the influence of yeast strains on the non-volatile and volatile compound contents were studied. Apple pomace mashes were fermented with Saccharomyces cerevisiae, Torulaspora delbrueckii, and sequential inoculation with Lachancea thermotolerans and S. cerevisiae to produce alcoholic beverages. Commercial non-pasteurized vinegar was used as a starter to ferment alcoholic beverages into vinegars. Ethanol, acetic acid, sugars and organic acids were determined using GC-FID. A total of 63 volatile compounds were detected in the samples using HS-SPME-GC-MS. Alcoholic beverages fermented with the sequential inoculation had the highest total content of organic acids, and pure inoculation with T. delbrueckii resulted in the highest total content of sugars. Selection of different yeast strains did not alter the content of ethanol or acetic acid, but it significantly influenced the composition of volatile compounds in alcoholic beverages and vinegars. Compared to initial apple pomace mash, significant increases in the contents of ethyl esters (up to 4810-folds), higher alcohols (up to 24-folds) and volatile acids (up to 1853-folds) were observed in fermented products depending on the yeasts used. The main volatile compounds in vinegars prepared from S. cerevisiae fermented beverage were 2-phenylethanol, octanoic acid, and decanoic acid, from T. delbrueckii beverage 2-methylpropanoic acid and 3-methylbutanoic acid, and from sequential fermentation ethyl acetate, and ethyl 2-hydroxypropanoate. In conclusion, non-Saccharomyces yeasts have potential to produce more complex aromatic profile to fermented products derived from by-products of apple juice processing.

Inactivation of foodborne pathogens on fruit juice with different solid contents by using pilot-scale 915 MHz microwave heating system

Fruit juices are often distributed in the form of concentrate for the sake of quality conservation and cost-reduction during distribution. The objective of this study is to investigate the effect of solid content on heating rate, dielectric properties, and foodborne pathogen inactivation in fruit juices when subjected to 915 MHz microwave heating. 50 mL of fruit juice with different solid contents were exposed to 915 MHz microwave at 3.0 kW for up to 60 s. Solid content was found to be an important factor for heating rate. The fastest heating rate was observed when concentrates were diluted by 50% (36 ° Brix apple and 30 °Brix orange juice). Though dielectric constant decreased along with increase in solid contents, different trends were observed for the dielectric loss factor. Especially, the fruit juices with higher magnitudes of the dielectric loss factor presented faster heating rate. Inactivation of the pathogens inoculated in the fruit juices was investigated by using E.coli O157:H7 and L.monocytogenes. In case of apple juice, 915 MHz microwave heating was most effective for 72 °Brix as 20 s operation resulted in over 5-log reduction for both pathogens. However, in orange juice, 30 °Brix was found to be most effective for 915 MHz microwave heating. In the inactivation mechanism analysis, cell membrane damage was observed when cells were exposed to higher solid contents due to low water activity. 915 MHz microwave heating did not include significant quality changes in terms color and total phenolic contents, except for 60 ° Brix of orange juice. The obtained results highlight the potential application of 915 MHz microwave heating for fruit juice processing

Identification and Mining of Functional Components of Polyphenols in Fruits of Malus Germplasm Resources Based on Multivariate Analysis.

Polyphenols are important functional components that have anti-cancer and anti-inflammatory effects. Apple fruit is rich in polyphenols and is one of the dietary sources of polyphenols. The polyphenol components and contents of the peel and pulp of 74 Malus sieversii (Led.) Roem. and 26 Chinese Malus germplasm resources were determined using ultra-high-phase chromatography (UPLC) and liquid chromatography-mass spectrometry (LC-MS). The results showed that 34 components were detected in the peel and 30 in the flesh, and that the polyphenol components and contents of the different germplasm resources were significantly different; the polyphenol content of Malus sieversii (Led.) Roem. was significantly higher than that of the other local varieties, and the polyphenol content in the peel was also higher than that in the flesh. Rutin, quercetin 3-O-arabopyranoside, kaempferol 3-O-rutinoside, and peonidin 3-O-galactoside were detected only in the peel. The total polyphenol content in the peel ranged from 949.76 to 5840.06 mg/kg, and the polyphenol content in the pulp ranged from 367.31 to 5123.10 mg/kg. The cluster analysis of polyphenol components and contents in peel and pulp showed that 100 Malus germplasm resources could be grouped into four categories. Principal component analysis of 34 kinds and 30 kinds of polyphenols in peel and pulp of 100 resources was performed. If the eigenvalue is greater than 1, eight and seven principal components are extracted, respectively. Five Malus resources with high polyphenol content in the peel and pulp were selected: 'XY-77' (peel: 5840.06 mg/kg, pulp: 5123.10 mg/kg; 'LF-09' (peel: 4692.63 mg/kg, pulp: 3729.79 mg/kg); '2012-5' (peel: 4377.61 mg/kg, pulp: 3847.54 mg/kg); '29028' (peel: 5088.05 mg/kg, pulp: 3994.61 mg/kg); and '11-01' (peel: 5154.45 mg/kg, pulp: 3616.15 mg/kg). These results provide us with information regarding the polyphenol composition and content of the wild apple resources and local cultivars. The high polyphenol content resources obtained by screening can be used as raw materials for the extraction of polyphenol components and functional fruit juice processing and can also be used as parents for functional fruit creation and variety breeding.