Not-from-concentrate pilot plant ‘Wonderful’ cultivar pomegranate juice changes: Volatiles

Changes in volatile, key odorants and bioactive properties of pomegranate juice during processing into concentrate

Key odorants of juices of pomegranate fruits of Hicaz variety obtained from different juice production stages (fresh: FrPJ, pasteurized: PPJ, filtered: FiPJ, and concentrated: CPJ) were examined. Processing significantly impacted the volatile compounds. The FrPJ and PPJ samples had higher concentrations of aroma compounds than the FiPJ and CPJ samples. A total of 38 aroma substances were identified in the FrPJ sample while 37, 35, and 21 compounds were detected in the PPJ, FiPJ, and CPJ samples, respectively. Phenylethyl alcohol was the dominant key odorant. The total phenolic contents (TPC) and antioxidant activities (AA) of the samples changed significantly. The CPJ sample had the highest TPC and AA due to increased release of phenolics during the concentration process; thus, this process increased the TPC and AA significantly, altering both aroma and bioactive properties. The results emphasize the importance of processing methods in preserving the nutritional and sensory qualities of pomegranate juice.

Effects of different sterilisation methods on the quality and flavor of non from concentrate (NFC) Actinidia arguta juice

Sterilisation is one of the most important means to extend the shelf life of fruit juices. In this paper, the effects of four sterilisation methods, ultraviolet (UV), ultrasonic (US), ultrahigh pressure (UHP) and low temperature long time (LTLT), on Actinidia arguta juice were investigated. The results showed that all four methods were able to reduce the microbial population below the safety limit, had no significant effect on pH, but increased the total soluble solids content and reduced the total acid content. UV, US and UHP were more effective in retaining nutrients, while LTLT significantly reduced chlorophyll, total sugars, total flavonoids, total phenols and ascorbic acid content (p < 0.05). UHP improved the colour better, while UV better preserved the original flavor. This study will provide an alternative strategy for thermal pasteurization of traditional NFC fruit juices.

Effect of ultra-high pressure homogenization on microorganism and quality of composite pear juice

In this study, composite pear juice was processed by ultra-high pressure homogenization (UHPH) at four different pressures (50, 100, 150, and 200 MPa) with six different temperatures (4, 20, 30, 40, 60, and 80°C), then microorganism and physicochemical and nutritional properties of the samples were investigated. The counts of total aerobic bacteria (TAB) and yeasts and molds (Y&M) were reduced by 0.89-4.72 log10 CFU/ml and 0.40-3.03 log10 CFU/ml after processing, respectively. There was no significant change on total soluble solid and color, but significant decreases of pH and particle size value were observed, and the antioxidant activity, total phenolic content, viscosity, and suspension stability significantly increased in treated samples. Compared to the untreated samples, polyphenol oxidase (PPO) and peroxidase (POD) activity of UHPH-treated samples varied between 97%-126% and 81%-165%, respectively, indicating that the PPO and POD activities could be inactivated or activated by UHPH. This study introduced proper temperature combined with UHPH could improve the microbial inactivation and the quality of the compound juice.

Elucidation of Volatiles, Anthocyanins, Antioxidant and Sensory Properties of cv. Caner Pomegranate (Punica granatum L.) Juices Produced from Three Juice Extraction Methods

This study deals with the characterization of the phytochemical profiles and antioxidant activities of cv. Caner pomegranate (Punica granatum) juices obtained from three different juice extraction methods including halved pomegranate (HPJ), arils (AJ), and macerated arils (MAJ) extraction for the first time. It was found that the type of the juice extraction process had substantial effects on the volatiles, anthocyanin compositions, and antioxidant activities of the samples. Results showed that the AJ sample (593 mg L^-1) had more anthocyanin compounds followed by HPJ (555 mg L^-1) and MAJ (408 mg L^-1) samples. GC-MS analysis revealed a total of 34 volatile compounds. The highest number of volatiles was found in the MAJ sample (1872 µg L^-1); thus, the aril maceration process played an important role in increasing the volatiles as compared to the HPJ (751.8 µg L^-1) and AJ (710.7 µg L^-1) samples. Sensory analysis showed that the HPJ sample was the most preferred and its general impression was higher as compared to the AJ and MAJ samples. The findings of this study elucidated that the juice extraction technique had a significant influence on the phytochemical profiles, sensory quality, and antioxidant activity of pomegranate juices.

Impact of Sugar Type Addition and Fermentation Temperature on Pomegranate Alcoholic Beverage Production and Characteristics

The present study focuses on the production of pomegranate alcoholic beverage (PAB) from juice of the Wonderful variety. The effect of fermentation temperature (15 and 25 °C) and type of sugar added (adjustment to 20 °Brix) on the physicochemical characteristics, bioactive compounds, and volatile composition were studied. Sucrose, concentrated pomegranate juice, concentrated grape juice, and honey were used to increase the initial sugar content. The produced PABs contained ethanol in concentrations ranging from 7.9 to 10.0% v/v and glycerol from 4.8 to 6.1 g L⁻¹. A decrease in total phenolics content, free radical-scavenging activity, and total monomeric anthocyanin content was observed following fermentation. Total flavonoids content appeared to increase after fermentation only in the cases of concentrated pomegranate and grape juice addition. In general, 22 volatile compounds were identified in PABs (13 esters, 2 fatty acids, and 7 alcohols). Major compounds detected were 3-methyl-1-butanol, 2-methyl-1-butanol, 2-phenylethanol, and ethyl acetate. These findings demonstrate the production prospect of PABs with increased ethanol content, while elaborating on the importance of fermentation temperature and the differences between the selected types of added sugars on end-product composition.

Evaluation of Yeast Strains for Pomegranate Alcoholic Beverage Production: Effect on Physicochemical Characteristics, Antioxidant Activity, and Aroma Compounds

In the present study, three commercial yeasts (for wine, beer, and cider) were evaluated for the production of pomegranate alcoholic beverage (PAB) from a juice of Wonderful variety. The physicochemical characteristics, antioxidant activity, and aromatic profiles of PABs were investigated before and after fermentation, while the effect of yeast strain and fermentation temperature (15 and 25 °C) was also evaluated. The PABs contained ethanol in the ranges of 5.6–7.0% v/v, in combination with glycerol (2.65–6.05 g L⁻¹), and low volatile acidity. Total flavonoid content, total phenolic content, free radical-scavenging activity, and total monomeric anthocyanin content appeared to decrease after fermentation, possibly due to hydrolysis, oxidation, and other reactions. In general, PABs retained 81–91% of free radical-scavenging activity, 29–41% of phenolics, 24–55% of flavonoids, and 66–75% of anthocyanins. The use of different yeast affected mainly flavonoids and anthocyanins, and yeast strain M02 resulted in the highest values after fermentation. In PABs, 30 different volatile compounds were identified, specifically 15 esters, 4 organic acids, 8 alcohols, and 3 terpenes. The principal component analysis showed that the fermentation temperature affected significantly volatile composition, whereas, among the yeasts, WB06 is the one that seems to differentiate. The findings of this study show that the selection of the appropriate yeast and fermentation temperature is very crucial and affects the characteristics of the final product.

Not-from-concentrate pilot plant 'Wonderful' cultivar pomegranate juice changes: Quality

Colorful fruits conveying astringent beverages providing well documented health-benefits may present clarification, turbidity and sedimentation problems. Hydraulic pressing whole 'Wonderful' pomegranates and ultrafiltration followed by high temperature short-time pasteurization was used to mimic the dominant U.S. commercial juicing protocol, delivering not-from-concentrate juices, stored at 4 and 25 °C for 3 months. A goal was to avoid expensive and complicated clarification and fining steps. Data were subjected to an analysis of variance and principal components analysis. Changes in quality attributes, organic acids and anthocyanidins are presented. Hydraulic pressing, ultrafiltration and initial pasteurization had minor effects on color parameters, organic acids and anthocyanidins. There were no significant temperature, time or factorial effects for all color parameters during storage of the not-from-concentrate pasteurized juices. However, there were significant time- and temperature-effect decreases in organic acids and anthocyanidins. This is the first report on quality attributes in ultrafiltered, pasteurized and stored not-from-concentrate 'Wonderful' pomegranate juice.

Microbial, nutritional, and organoleptic quality of pomegranate juice following high-pressure homogenization and low-temperature pasteurization

This study investigated the effects of high-pressure homogenization (HPH) on microbial, nutritional, and organoleptic qualities of pomegranate juice. Juices subjected to HPH at 100 and 150 MPa were compared to those subjected to thermal pasteurization at 55, 65, and 75 °C for 15 s, and to combined treatments. Physicochemical properties of pomegranate juices, such as color, pH, acidity, and total soluble solids, were marginally affected by either treatment. Significant microbial inactivation for the juices inoculated with Escherichia coli and yeast was achieved during 28 days of shelf life by HPH at 150 MPa, followed by thermal treatment at 65 °C. There was no significant difference in ascorbic acid levels between the treated and fresh juice. Total polyphenol content and antioxidant activity were measured to be higher in case of both treatment methods. Analyzing treated HPH samples with electronic tongue and nose showed similar flavor profiles to the fresh juice. PRACTICAL APPLICATION: The work shows the benefits of using the advanced high-pressure homogenization (HPH) compared to common thermal treatment used today in fruit juice pasteurization. HPH is capable to provide sufficient reduction in microbial with better nutritional and organoleptic quality. In this manuscript, we showed the potential of HPH as alternative method for pasteurization on a highly healthy fruit like pomegranate. The work describes the advantages in HPH process through comprehensive analysis for nutritional, microbial, and sensorial quality.

Assessment of the Usefulness of the Twin-Screw Press in Terms of the Pressing Efficiency and Antioxidant Properties of Apple Juice

The paper presents the possibility of applying a twin-screw press for juice extraction from apples with different textural properties. The research was carried out with six different varieties; namely, Granny Smith, Modi, Ligol, Lobo, Boscop and Szampion. During the experiment, the following properties were measured: texture properties, pressing yield and polyphenolic content; and ascorbic acid content and antioxidant activity both in raw apples and apple juice. Based on the analysis, three hardness levels of apples can be distinguished, impacting the course of juice pressing in a twin-screw press (low hardness below 30 N, medium hardness 30–50 N and high hardness 50 N). The study showed that only high hardness apples are suitable for pressing on a twin-screw press. The mechanism by which texture properties influence the juice pressing process in the studied press was explained. It was further demonstrated that the hardness of apples has a positive impact on the degree of extraction of polyphenols and ascorbic acid into apple juice. This is caused by the different fracture patterns of tissues with different mechanical properties. High hardness apples (Granny Smith and Modi) were characterized by a considerably greater degree of bioactive substance extraction into juice than medium hardness apples.

Potential of the Probiotic Lactobacillus Plantarum ATCC 14917 Strain to Produce Functional Fermented Pomegranate Juice

In this research survey the application of probiotic strain Lactobacillus plantarum ATCC 14917 in pomegranate juice fermentation is sought. Pomegranate juice was fermented for 24 h and then it was stored 4 for 4 weeks. Cell viability retained in high levels after the 24 h of fermentation and storage for 4 weeks (above 8.8 log cfu/mL), while fermented pomegranate juice was scored better at the 4th week of storage compared to non-fermented pomegranate juice. The probiotic strain was effective regarding lactic acid fermentation as was proved through sugar and organic acids analysis. Concentration of ethanol was maintained at low levels (0.3–1% v/v). Fermented pomegranate juice contained more and in higher percentages desirable volatile compounds (alcohols, ketones and esters) even at the 4th week of cold storage compared to non-fermented juice. Antioxidant activity (150.63 mg Trolox equivalent (TE)/100 mL at the 2nd week) and total phenolic content (206.46 mg gallic acid equivalents (GAE)/100 mL at the 2nd week) were recorded in higher levels for all the storage time compared to non-fermented juice.

Assessment of Volatile Compounds Evolution, Antioxidant Activity, and Total Phenolics Content during Cold Storage of Pomegranate Beverage Fermented by Lactobacillus paracasei K5

A recently isolate from feta type cheese, potential probiotic strain Lactobacillus paracasei K5, was applied for pomegranate juice (Punica granutum L.) fermentation. Fermentations were carried out for 24 h followed by the storage of pomegranate juices at 4 °C for 4 weeks. The parameters examined were a composition of volatile compounds, antioxidant activity, total phenolic content, and consumers’ acceptance. The results were encouraging showing that lactic acid fermentation enhanced the composition of volatile compounds even at the fourth week of storage. Increased antioxidant activity (151.44 mg TE/100 mL at the second week) and total phenolics content (285 mg GAE/100 mL at the third week) were observed for all the storage times compared to the initial pomegranate beverage. The fermented pomegranate beverage received better scores for the last 3 weeks of cold storage compared to the non-fermented one. Likewise, L. paracasei K5 was proved to be suitable for the production of functional pomegranate beverages with enhanced aromatic characteristics and high nutritional value.