Search Results (32)

Apple juice is widely consumed across global beverage markets. Its colour and cloudy appearance play a crucial role in consumer perception. Various physical treatments are available to modify juice turbidity and preserve colour, among which filtration and high-pressure homogenisation are considered the most respectful to the raw juice composition. In this study, red apple juice from the Kissabel^® Rouge cultivar was filtered using membranes ranging from 100.0 to 0.2 μm and homogenised at pressures from 20 to 60 MPa. The physicochemical properties were then evaluated after 205 days of storage at two different temperatures. Microfiltration (<5.0 μm) increased juice lightness (87 vs. 66), but compromised cloud and colour stability by reducing cloudiness by 15 days compared with the unfiltered juices. Homogenisation increased turbidity, both in absolute value and during storage, which is typically appreciated in 100% apple juices. Finally, colloidal stability was affected by both treatments; combining mild filtration with low homogenisation pressure yielded the highest colloidal repulsion (−16.3 mV). Elevated storage temperatures generally diminished juice quality in terms of colour tone and intensity, and accelerated particle sedimentation. Full article

Fermented fruit juices are considered functional beverages because they contain bioactive compounds derived from plant materials and produced by the microorganisms involved in fermentation. The composition of these beverages can vary depending on the strain used. This study aimed to determine the effect of different microorganisms conducting lactic acid fermentation on the chemical composition and bioactive component content of naturally cloudy fermented pear and plum juices. The process used Lactiplantibacillus plantarum K7 bacteria, which were isolated during sauerkraut fermentation, as well as Lachancea thermotolerans PYCC6375 and Lachancea fermentati PYCC5883 yeast cultures, which have poor ethanol fermentation capabilities. The pH, acidity, sugars (HPLC), free amino nitrogen, selected organic acids (HPLC), color (CIELAB), polyphenols (HPLC), volatiles (GC-MS), aroma-active volatiles (GC-MS-O), and sensory characteristics were analyzed. The fermented juices obtained were rich in organic acids (of plant and microbial origin), polyphenols, and had a reduced sugar content (with polyols replacing glucose and fructose), as well as a low alcohol content (<0.2%). At the same time, all three microorganisms significantly enhanced the fruity aroma of the juices. Lachancea yeasts proved to be a viable alternative to lactic acid bacteria for producing fermented juices and were significantly better suited to fermenting plum juices. The highest polyphenol content and highest consumer preference rating were obtained with plum juices fermented with L. fermentati yeast. Full article

Cloudy huyou juice is increasingly popular for its unique flavor, but flocculent precipitation after cold storage and thawing affects its sensory quality and increases production costs. This study optimized the clarification of thawed cloudy huyou juice using a composite of carboxymethyl chitosan (CC) and sodium alginate (SA), prepared via ionic and covalent crosslinking. The composite was characterized by SEM, FTIR, and thermal analysis. Transmittance was used to evaluate clarification performance. The effects of dosage, adsorption time, and temperature were first assessed through single-factor experiments, followed by optimization using a Box–Behnken response surface methodology. The composite significantly improved clarity (p < 0.05), reaching 85.38% transmittance under optimal conditions: 22 mg dosage, 80 min time, and 38 °C. The composite dosage and temperature were the most influential factors. Reusability tests showed declining performance, with the transmittance dropping to 57.13% after five cycles, likely due to incomplete desorption of adsorbed compounds. These results suggest that the CC-SA composite is an effective and reusable clarifying agent with potential for industrial applications in turbid fruit juice processing. Full article

Fermented apple cider is a refreshing alcoholic drink known since ancient times, and it is obtained by fermenting apple fruit juice. Using the standards of alcohol concentration (up to 8%) and carbonation, it belongs to drinks similar to beer. It can be produced using wild yeasts, but currently a fermentation starter can be purchased. This work aims to produce fermented cider using commercial pasteurized juices: clear apple juice and organic cloudy juice using commercial yeast for cider production. After fermentation, the physico-chemical characteristics of the drink were determined, alongside volatile compounds of the freshly produced ciders, as well after 1, 2, and 3 weeks of maturation. Acids, alcohols, carbonyl compounds, terpenes, esters, and volatile phenols were determined using headspace–solid phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC/MS). The results show that the fermentation was slower (14 days) in the cloudy juice in contrast to the sample produced from clear apple juice (10 days). Also, the volatile compounds related to aroma were abundantly found in the cider produced from cloudy apple juice compared to the cider produced from the clear apple juice. The conducted sensory analysis was in favor of cloudy juice. Full article

This study evaluates the feasibility and effectiveness of using immobilized pectinase enzymes for juice processing to reduce cloudiness while preserving nutritional and bioactive properties. The research is driven by the increasing demand for innovative food products that offer enhanced functionality and health benefits. It focuses on the development and application of immobilized biocatalysts in bioprocessing, specifically using pectinase encapsulated in a sol–gel matrix. Reaction parameters for the interaction between immobilized pectinase and its primary substrate, pectin, were optimized through systematic experimentation. Optimal conditions were established, achieving enhanced enzyme activity and stability with 0.15 g of lens-shaped capsules containing 10.0 mg/mL pectinase in 24-well microplates as microreactors. Kinetic studies indicated improved substrate affinity after immobilization (K_m = 0.115 mg/mL), particularly when magnetized (K_mi = 0.041 mg/mL). Operational stability and reusability assessments demonstrated potential for extended use with magnetized pectinase capsules retaining higher residual activity after a fourth reuse cycle (155% > 75%). The application of immobilized pectinase in processing peach nectar successfully reduced cloudiness and increased the release of bioactive compounds, enhancing antioxidant and anti-inflammatory activities, as evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and the albumin method, respectively. In vitro digestion studies revealed dynamic activity profile changes, highlighting the impact of juice bioprocessing on bioavailability. Full article

The high amount of starch in fruits is responsible for its post-processing cloudiness. In the current study, α-amylase from porcine pancreases was immobilized onto carboxymethyl cellulose/polyacrylamide (CMC/PAM) hydrogel. This in-house-built CMC/PAM-Amy hydrogel offers a more efficient and sustainable solution for apple juice clarification. To acquire the best immobilization efficiency, the concentration of glutaraldehyde crosslinker was optimized. Biocatalytic characterization studies were brought into consideration for free and immobilized α-amylase. The synthesized native and immobilized CMC/PAM-Amy hydrogels were also characterized using SEM, FTIR and XRD. Under ideal circumstances, the activity of CMC/PAM-Amy was up to 604 μmolmin⁻¹, and its immobilization efficiency was 96.29 ± 1.15%. A kinetic parameters study resulted in a conspicuously lowered Km value for immobilized amylase, signifying its higher affinity for its substrate. CMC/PAM-Amy showed a half-life (t_1/2) 3.5 times higher than free-Amy at 50, 55 and 60 °C. The higher values of the inactivation rate constant (k_d), free energy of inactivation (ΔG*), enthalpy of inactivation (ΔH*) and change in entropy (ΔS*) of CMC/PAM-Amy manifested the enhanced thermal stability of amylase after immobilization. A reusability study revealed that immobilized amylase retained roughly 70% of its initial catalytic activity after six successive repetitions of the process. CMC/PAM-Amy displayed improved recycling ability operational stability and biocatalytic activity, rendering it an auspicious tool in decreasing the starch content of crude apple juice to about 61% of its total starch content before treatment. Moreover, the values of Brix, viscosity, acidity and turbidity were also decreased in CMC/PAM-Amyclarified apple juice. Therefore, immobilized amylases with other industrial enzymes could be an efficient tool for potential industrial application. Full article

The aim of this study was to evaluate the quality of cloudy beetroot juice powders with or without a carrier obtained by spray drying using an innovative method of dehumidified air that enabled drying in low temperatures and, consequently, with a reduced carrier content. Phenolic content, betacyanin content, antioxidant activity and the content and types of aromatic compounds of the produced powders were examined. Powders obtained at a lower temperature (90 °C) without carriers were characterized by the highest share of aromatic volatile compounds, the highest content of betalains and polyphenols and the highest antioxidant activity. The addition of carriers (including the variant with added pomace as a natural type of carrier) did not indicate the protection of the active substances present in the juice. The powders obtained with carrier addition compared with those without the carrier addition were characterized by lower antioxidant activity, lower content of betalains and polyphenols and a lower amount of aromatic volatile compounds. No significant differences were found in the content of bioactive and aromatic compounds between powders obtained using different carriers (skim milk powder, Nutriose, maltodextrin and kleptose). Full article

Background: Exercise and the consumption of sugars result in a dysfunction of the intestinal barrier (IB). Here, we determined the effect of sugar in a natural matrix on the intestinal barrier after moderate (A) and intensive endurance exercise (B). Method: The IB function was determined before (pre) and after running (post), and 120 and 180 min after consuming the drink by measuring serum endotoxin concentrations (lipopolysaccharides—LPS), IL-6, CD14, and i-FABP. In study A, nonspecifically trained participants (n = 24, males and females, age 26 ± 4) ran for one hour at 80% of their individual anaerobic threshold (IAT). After finishing, the runners consumed, in a crossover setup, either 500 mL of water, diluted cloudy apple juice (test drink), or an identical drink (placebo) without the fruit juice matrix (FJM). In study B, the participants (n = 30, males and females, age 50 ± 9) completed an ultra-marathon run, were divided into groups, and consumed one of the above-mentioned drinks. Results: Study A: Exercise resulted in a significant increase in serum LPS, i-FABP, and IL-6, which decreased fast after finishing. No impact of the different drinks on LPS i-FABP, or IL-6 could be observed, but there was an impact on CD14. Study B: The ultra-marathon resulted in a strong increase in serum LPS, which decreased fast after finishing in the water and test drink groups, but not in the placebo group. Conclusions: The consumed drinks did not affect the kinetics of IB regeneration after moderate exercise, but impacted CD14 serum concentrations, indicating possible beneficial effects of the FJM on the immune system. After an ultra-marathon, IB function regenerates very fast. The intake of sugar (placebo) seems to have had a negative impact on IB regeneration, which was diminished by the presence of the FJM. Full article

Fruit consumption guarantees the supply of most of the necessary nutrients for a complete and balanced diet, as it is a relevant source of vitamins, minerals, and antioxidants. In particular, pomegranate has very interesting medicinal properties, such as an anti-inflammatory effect and the protection of the cardiovascular system, among others. During pomegranate juice production, it appears cloudy and must be clarified to remove suspended solids such as colloids and high-molecular weight tannins. The membrane clarification process is a cost-effective alternative to the conventional methods, resulting in a high-quality product. In this work, the clarification of pomegranate juice using the Triple System Model F1 membrane module was carried out for the Mollar and Wonderful varieties with early and late maturity. Three ultrafiltration membranes with different molecular weight cut-off and different chemical compositions were used. The rejection coefficient and permeate flux (which represent the selectivity of the membranes and the process efficiency, respectively) were measured. GR-40PP showed the best results in terms of membrane selectivity and process efficiency, achieving adequate physicochemical juice parameters. Regarding the comparison of the maturity degree, in general terms, the Mollar variety showed better results. Ripe pomegranates showed greater selectivity, while the process efficiency was higher for the early samples. Full article

The aim of this study was to investigate the rheological properties, particle size distribution, color change, and stability of lily juice under different ultrasonic treatment conditions (152 W, 304 W, 456 W, 608 W, and 760 W). The results showed that the lily juice exhibited non-Newtonian shear thinning behavior, and the viscosity decreased with the increase in ultrasonic power. Under ultrasonic treatment conditions, there was no significant change in the pH value and zeta potential value of the samples. The content of cloudy value and total soluble solids (TSS) increased gradually. However, both the sedimentation components and centrifugal sedimentation rate showed a downward trend and an asymptotic behavior. In addition, high-power ultrasound changed the color index (L* value decreased, a* value increased), tissue structure, and particle distribution of the sample, and small particles increased significantly. To sum up, ultrasonic treatment has great potential in improving the physical properties and suspension stability of lily juice. Full article

This study investigated the effects of thermosonication (TS) on the quality of blackcurrant juice, along with its physicochemical properties, bioactive compounds, antioxidant capacity, and microbiological and sensory qualities. The treatments included raw juice (RJ), pasteurized juice (90 °C, 1 min, PJ), and thermosonicated juice (480 W, 40 kHz at 40, 50, or 60 °C, for 10, 20, 30, or 40 min, TJ). The results indicated that the effects of pasteurization and thermosonication on the pH, total soluble solids, and titratable acidity of the juice were not significant (p > 0.05). However, the cloudiness, browning index, and viscosity were significantly increased (p < 0.05), and the color properties of the blackcurrant juice were improved. The total phenolic, flavonoid, and anthocyanin contents of TJ (treated at 50 °C for 30 min) were increased by 12.6%, 20.9%, and 40.4%, respectively, and there was a notable decline in ascorbic acid content after the pasteurization treatment, while the loss was minor in all TJ samples compared with RJ. The scavenging ability of 1,1-diphenyl-2-pyridyl and hydroxyl radicals increased to 52.77% and 50.52%, respectively, which were significantly (p < 0.05) higher than those in the RJ and PJ samples. In addition, both pasteurization and thermosonication resulted in a significant (p < 0.05) reduction in microbial counts, while there were no significant (p > 0.05) differences in the sensory parameters compared with the RJ samples. In conclusion, this study suggests that TS is an effective method that can be used as an alternative to pasteurization to improve the quality of blackcurrant juice. Full article

This study investigated the quality characteristics of pasteurized and thermosonicated bor-thekera (Garcinia pedunculata) juices (TSBTJs) during storage at 4 °C for 30 days. Various parameters, including pH, titratable acidity (TA), total soluble content (TSSs), antioxidant activity (AA), total phenolic content (TPC), total flavonoid content (TFC), ascorbic acid content (AAC), cloudiness (CI) and browning indexes (BI), and microbial activity, were analyzed at regular intervals and compared with the quality parameters of fresh bor-thekera juice (FBTJ). A multi-layer artificial neural network (ANN) was employed to model and optimize the ultrasound-assisted extraction of bor-thekera juice. The impacts of storage time, treatment time, and treatment temperature on the quality attributes were also explored. The TSBTJ demonstrated the maximum retention of nutritional attributes compared with the pasteurized bor-thekera juice (PBTJ). Additionally, the TSBTJ exhibited satisfactory results for microbiological activity, while the PBTJ showed the highest level of microbial inactivation. The designed ANN exhibited low mean squared error values and high R² values for the training, testing, validation, and overall datasets, indicating a strong relationship between the actual and predicted results. The optimal extraction parameters generated by the ANN included a treatment time of 30 min, a frequency of 44 kHz, and a temperature of 40 °C. In conclusion, thermosonicated juices, particularly the TSBTJ, demonstrated enhanced nutritional characteristics, positioning them as valuable reservoirs of bioactive components suitable for incorporation in the food and pharmaceutical industries. The study underscores the efficacy of ANN as a predictive tool for assessing bor-thekera juice extraction efficiency. Moreover, the use of thermosonication emerged as a promising alternative to traditional thermal pasteurization methods for bor-thekera juice preservation, mitigating quality deterioration while augmenting the functional attributes of the juice. Full article

This research is the first study on the influence of juicing methods on the ‘Aurora’ haskap juice quality. Three common juice extraction methods, namely, using a steam juicer, a centrifugal juicer, and a bladder wine press, were applied for haskap juice extraction. Both physicochemical assays and tests of antioxidant activities were employed to evaluate the qualities of the haskap juice. Generally, the centrifugal juicer increased and the steam juicer reduced concentrations of measured juice components relative to the press. The juice from the centrifugal juicer had the highest cloudiness. Sugar concentrations were about 40% lower in steam juice compared to the centrifugal juicer. Pressed juice had a slightly lower soluble solid content than the juice made with the centrifugal juicer and concentrations of glucose and fructose were similar between these methods. The methods altered pH and malic acid content without affecting the concentrations of tartaric and malic acids. Similar effects of juicing methods were seen in secondary compounds associated with health benefits and antioxidant capacities. Anthocyanin concentrations in press and centrifugal juicer extracts were similar, about 1.6 times higher than steam juicer extracts. Total phenolics and antioxidant activities were from two to four times higher in the centrifugal juicer extraction compared to steam juicing. Ascorbic acid and total flavonoid content in the haskap juice was increased by centrifugal juicing and decreased by steam juicing compared to the press. Overall, the juice extracted with the centrifugal juicer had concentrations of juice components that were 1.5–2 times higher than the steam juicer. The pressed juice had similar to slightly lower concentrations of components compared to the centrifugal juicer. Full article

Triterpenoids are a group of secondary plant metabolites, with a remarkable pharmacological potential, occurring in the cuticular waxes of the aerial parts of plants. The aim of this study was to analyze triterpenoid variability in the fruits and leaves of three apple cultivars during the growing season and gain new insights into their health-promoting properties and fate during juice and purée production. The identification and quantification of the compounds of interest were conducted using gas chromatography coupled with mass spectrometry. The waxes of both matrices contained similar analytes; however, their quantitative patterns varied: triterpenic acids prevailed in the fruits, while higher contents of steroids and esterified forms were observed in the leaves. The total triterpenoid content per unit area was stable during the growing season; the percentage of esters increased in the later phases of growth. Antioxidative and anti-inflammatory properties were evaluated with a series of in vitro assays. Triterpenoids were found to be the main anti-inflammatory compounds in the apples, while their impact on antioxidant capacity was minor. The apples were processed on a lab scale to obtain juices and purées. The apple purée and cloudy juice contained only some of the triterpenoids present in the raw fruit, while the clear juices were virtually free of those lipophilic compounds. Full article

Organic food quality is based on processing. While the EU organic production regulation focuses on agricultural production, private standards provide more detailed information about further processing. For the development of organic processing, practitioner perspectives can provide valuable input. To get insight into practitioner perspectives, we conducted semi-structured expert interviews with nine employees of seven partly organic juice processing companies from Germany and Austria. Interview topics were (i) quality of organic juice processing in general, (ii) assessment of specific processing techniques, (iii) product quality of organic juice and (iv) flow of information between producer and consumer. We conducted a thematic analysis. We found that the experts’ understanding of process quality mostly includes more aspects than the EU organic production regulation. It covers the whole food chain plus aspects of social and environmental sustainability. The experts prefer directly bottled juice of local raw materials but chiefly accept juice made from concentrate of exotic raw materials because of environmental concerns. Organic juice is preferred when it is cloudy and natural fluctuations are interpreted as an indicator of natural quality. The experts report that consumer information is challenging because of low food literacy. Raising this might help reduce the number of processed juices on the market. Full article