Juice Components Research Articles

Inactivation activity and mechanism of high-voltage pulsed electric fields combined with antibacterial agents against Alicyclobacillus spp. in apple juice.

Alicyclobacillus spp. are crucial factors affecting the quality of fruit juice, so it is very important to control their contamination. In this study, the inactivation activity and mechanism of high-voltage pulsed electric fields (HVPEF) combined with antibacterial agents against Alicyclobacillus spp. in apple juice were investigated. It was found that under the optimal conditions of electric field strength 9.6kV/cm, treatment time 20min, frequency 1000Hz, and duty ratio 50%, HVPEF treatment could reduce bacteria by 1.89-4.76 log CFU/mL. Moreover, the inactivation activities of six antibacterial agents (propyl paraben, glycerol monocaprate, octyl gallate, heptyl paraben, nisin, carvacrol) alone and their combination with HVPEF were further investigated. The results showed that with the combined treatment, the minimum bactericidal concentrations of carvacrol, nisin, and heptyl paraben were reduced by >50% to 1mg/mL, 10IU/mL, and 0.02mg/mL, respectively. Based on this, the most resistant strain of A. acidoterrestris (DSM 3922) was identified to elucidate the inactivation mechanism. It was demonstrated that the antibacterial process could alter the permeability and fatty acid composition of the cell membrane, causing the cells to deform and shrink, leading to leakage of intracellular proteins, and also affect the synthesis of ROS and ATP, ultimately resulting in bacterial death. In addition, the various treatments had no significant effect on the soluble solids content, titratable acid, soluble sugar content, organic acids and aroma components of apple juice. The combination of HVPEF treatment and antibacterial agents could effectively maintain the quality of apple juice.

Co-fermentation of Lactiplantibacillus and Streptococcusccus enriches the key-contribution volatile and non-volatile components of jujube juice

Lactic acid bacteria (LAB) fermentation can enhance the quality and flavor characteristics of fruit juice. Herein, the impact of individual Lactiplantibacillus plantarum subsp. plantarum (L. plantarum) or Streptococcus thermophilus (S. thermophilus) and co-fermentation of them on jujube juice was compared, and their quality characteristics, volatile and non-volatile compounds were investigated. The results showed that the co-fermentation of selected LAB strains effectively improved the quality of fermented jujube juice (FJJ) as expected, and the types and content of volatile organic compounds (VOCs) increased in FJJs. Among them, the co-fermented sample posed relatively high content of aroma-active compounds with OAV ≥1 (nonanal, decanal, etc), benzaldehyde and acids compared with others, contributing to a more attractive and pleasant flavor. Moreover, non-targeted metabolomic analysis identified 114 and 79 differential metabolites (DMs) between co-fermented and L. plantarum fermented or S. thermophilus fermented samples, respectively. Notably, carboxylic acids and their derivative metabolites as well as organic acids were the crucial components affecting the quality of FJJ. Furthermore, metabolic pathways of DMs of different samples were predominantly enriched in “biosynthesis” and “metabolism”, such as aline, leucine, and isoleucine biosynthesis pathway. Therefore, co-fermentation could enrich the acids, essential amino acid, and VOCs, thereby improving its quality and flavor characteristics. The correlation analysis revealed that most of key VOCs were positively or negatively correlated with D-galacturonate, indicating the importance of D-galactose pathway. Thus, this study provided a theoretical foundation for enhancing the quality and flavor of jujube juice through LAB co-fermentation, offering valuable insights for improving the juice processing.

Effect of dynamic high-pressure microfluidization and thermal processing on quality and volatile components of NFC tomato juice

In this study, tomato juice was processed using both dynamic high-pressure microfluidization (DHPM) and thermal processing (TP) to investigate their effects on the quality and volatile components of not-from-concentrate (NFC) tomato juice. Both DHPM (400 MPa, 25 ℃) and TP (95 ℃, 3 min) achieved sterilization and improved the brightness of the juice. TP resulted in severe loss of ascorbic acid with only 49 % retention. Significant color change after TP (ΔE = 1.62), and severe browning. DHPM treatment and TP reduced the acidity of tomato juice by 26.67 % and 22.67 %, respectively. DHPM improved tomato juice stability, and the D [3,4] and turbidity of the tomato juice decreased from 98.1 to 21.2 μm and from 55.64 to 24.58 nephelometric turbidity units (NTU), respectively. The identification of volatile components in tomato juice by gas chromatography-ion mobility spectrometry (GC-IMS) showed that the content of 37 volatile components in tomato juice increased after DHPM treatment. The contents of 2-furanmethanol and 2-ethylpyrazine, the off-flavor compounds of the cooking flavor, increased more after TP. The characteristic aroma of tomato, 2-phenylacetaldehyde, increased after processing. The study results provide basic theoretical data for tomato juice processing.

Effects of different concentration methods on the quality and volatile components of sea buckthorn clear juice

Sea buckthorn clear juice is clarified and transparent, maintains high nutritional value and flavor, and is favored by consumers. Herein, we used sea buckthorn clear juice as a raw material to determine the effects of three concentration methods, namely vacuum thermal concentration, vacuum freezing concentration and reverse osmosis membrane concentration, on the quality and volatile components of the juice. The results showed that the browning index of the sea buckthorn clear juice increased by 54.7% after the vacuum thermal concentration, thereby a darker color. The reason was the concentration treatments significantly increased 5-hydroxymethylfurfural content (p < 0.05) in the juice. Furthermore, polyphenol, flavonoid, and ascorbic acid contents were reduced by 21.3%–26.01%, 8.4%–23.94%, and 17.35%–22.02%, respectively, after subjecting the juice to the concentration treatments. Compared with the thermal concentration methods, the nonthermal concentration method better preserved the characteristic sweet and sour flavor of sea buckthorn clear juice as well as reduced the relative content of aromatic components with irritating bad odors, such as aldehydes (7.24% vs. 10.16%) and acids (8.2% vs. 8.82%), in sea buckthorn clear juice. In conclusion, the nonthermal concentration method can better maintain the quality and aroma of sea buckthorn clear juice.

Pulsed light processing of sugarcane juice: quality evaluation and microbial load assessment.

Freshly extracted sugarcane juice is an ideal substrate for microbial fermentation and browning reactions. The present study is the first report on the potential of pulsed light (PL) processing in improving microbial stability with the retention of major bioactive. PL processing at different levels of voltage (2.1-2.7 kV) and number of pulses (100-200) was explored. The present study aimed to investigate the impact of PL processing on the quality of sugarcane juice, bioactive composition and microbial load. The microbial load, such as aerobic mesophiles, yeast and mold, and total coliform, was reduced to below 1 log colony-forming units mL-1 in juice samples subjected to intense PL treatment at 2.7 kV. The maximum value of the total color difference of the sugarcane juice was below 4.0, even at extreme levels of PL process parameters. In comparison with the unprocessed juice, the reduction in total phenols (Folin ciocalteu reagent assay) and the total antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay) was limited to 6% and 16.7%, respectively, when treated at 2.7 kV/200 pulses. The pH and total soluble solids of the juice remained unaffected in all the processed samples. Among the process parameters considered, the treatment voltage was found to significantly affect the quality parameters and microbial load. PL processing at 2.1 kV/170 pulses gave an optimally processed juice with a microbial load below the permissible limit and desirability value of 0.77. The results suggest that the PL treatment is effective for enhancing the microbial stability and maintaining the bioactive components of the sugarcane juice. Furthermore, the outcomes from the present study are expected to pave the way for further in-depth investigation of the effect of PL treatment on the critical quality attributes and shelf life of sugarcane juice. The technology will be useful for adoption by different stakeholders, including manufacturers and retailers in the food processing sector. © 2024 Society of Chemical Industry.

Studying the components of beet juice for the production of kvass

Studying the components of beet juice for the production of kvass

D-Limonene Is the Active Olfactory Attractant in Orange Juice for Bactrocera dorsalis (Insecta: Diptera: Tephritidae).

The oriental fruit fly, Bactrocera dorsalis (Hendel), poses a significant threat to the global fruit industry, causing damage to diverse fruits like citrus, mango, and guava. Chemical pesticides have limited effectiveness, and pesticide residues and pesticide resistance are pressing issues. Therefore, it is essential to develop environmentally friendly pest control methods to address this problem. Behavior-modifying chemicals, including male attractants and intersex protein baits, play a critical role in the control of B. dorsalis. The mature host fruit serves as both an oviposition site and food source under natural conditions, making it a potential attraction source for oriental fruit flies. Orange, Citrus sinensis, is a main host of B. dorsalis, and commercial orange juice is a common attractant for the egg laying of B. dorsalis. Although it can both attract and elicit oviposition behaviors in B. dorsalis adults, its active components are still unclear. This study utilized analytical chemistry, behavioral tests, and electrophysiology to identify the active components of commercial orange juice that attract B. dorsalis, with the aim of providing a reference for the development of behavior-modifying chemical-based techniques to control B. dorsalis. Five compounds with a high abundance were identified via a GC-MS, including D-Limonene, butanoic acid ethyl ester, β-myrcene, linalool, and α-terpineol. Behavioral and electrophysiological experiments uncovered that D-Limonene was the active substance that was the main attractant in the mixture of these five substances, evoking a strong electrophysiological response in adult B. dorsalis. D-Limonene strongly attracts adult B. dorsalis only when they are sexually mature, and the attraction is not rhythmic. Olfaction plays a leading role in the attraction of D-Limonene to adult B. dorsalis, and Orco-/- mediates the perception of D-Limonene by B. dorsalis. Overall, D-Limonene is one of the key attractant compounds for B. dorsalis in the volatile compounds of commercial orange juice, offering possible support for the development of behavior-modifying chemical-based technology to control B. dorsalis in the future.

Ultra-high pressure treatment improve the content of characteristic aromatic components of melon juice from the view of physical changes.

The effectiveness of ultra-high pressure (UHP) technology in retaining the flavor of fresh fruit and vegetable juices has been acknowledged in recent years. Along with previously hypothesized conclusions, the improvement in melon juice flavor may be linked to the reduction of its surface tension through UHP. In this paper, the particle size, free-water percentage, and related thermodynamic parameters of melon juice were evaluated in a physical point for a deeper insight. The results showed that the UHP treatment of P2-2 (200 MPa for 20 min) raised the free water percentage by 7,000 times than the other treatments and both the melting enthalpy, binding constant and Gibbs free energy of P2-2 were minimized. This significantly increased the volatility of characteristic aromatic compounds in melon juice, resulting in a 1.2-5 times increase in the content of aromatic compounds in the gas phase of the P2-2 group compared to fresh melon juice.

Improvement mechanism of umami peptides in oyster juice by cooperative enzymolysis of alcalase and trypsin based on peptidomics and molecular docking

Traditional oyster juice is a by-product of dried oyster through stew of whole oyster, leading to few umami components from oyster. In this study, cooperative enzymolysis of alcalase and trypsin was used to improve the umami components of oyster juice. The optimal enzymolysis conditions of oyster juice included enzyme concentration of 0.4% alcalase and 0.1% trypsin, enzymolysis time of 1.5 h, and solid-liquid ratio of 1:8, and the amino acid nitrogen content in these conditions reached 0.53 g/L, obviously higher than that in non-enzymolysis group (0.27 g/L). The total free amino acids and peptides in the oyster juice were significantly improved by cooperative enzymolysis. After identification by peptidomics, 159 umami peptides were screened and 5 most abundant umami peptides were used to reveal the taste mechanism by molecular docking with the umami receptor T1R1/T1R3. Umami peptides mainly interacted with Arg56, Thr55, Glu48 and Arg64 in T1R3 through hydrogen attractive charge, conventional hydrogen bond, and carbon hydrogen bond, while hydrogen bond, interpolated charge, hydrophilicity, ionizability, and solvent accessible surface were the main surface forces. The “DED” structure in umami peptides was prone to interact with T1R3 receptor. This study provides a novel approach for enhancement of umami components in oyster juice.

Optimization of bioactive components of ultrasound treated white grape juice

Grapes are among the most commonly produced fruits worldwide, thanks to their ease of cultivation in terms of climate and soil requirements. Owing to their abundant vitamins, bioactive compounds and minerals incorporating them into one’s diet is advised for promoting human health. The bioactive components of ultrasound-treated white grape juice were optimised by response surface methodology (RSM). In addition, untreated white grape juice (C-WGJ), ultrasound treated white grape juice (U-WGJ) and thermally pasteurized white grape juice (P-WGJ) samples were compared for total phenolics compound (mg GAE/L), total flavonoids (mg CE/L) and DPPH (% Inhibition) parameters. The scientific investigation employed RSM, a widely favored approach. During the study, ultrasound process parameters such as amplitude (40, 50, 60, 70 and 80%) and duration (2, 4, 6, 8 and 10 minutes) were manipulated. The responses to the process application were assessed through analyses of total phenolic content (TPC), total flavonoid content (TFC) and DPPH (1,1-Diphenyl-2-Picryl Hydrazyl). The model achieved commendably high R2 values following optimization through RSM. One-way ANOVA for DPPH value, TFC and TPC of samples, both amplitude and duration exhibited statistically significant effects (p&amp;lt;0.001). The effectiveness of ultrasound treatment in increasing bioactive components in untreated white grape juice is higher than thermal pasteurization treatment. Through the optimization process, the best bioactive values for white grape juice were achieved, measuring 42.3 mg CE/L for TFC, 55.5% inhibition for DPPH and 440.3 mg GAE/L for TPC. Ultrasound applied to white grape juice proved to be more effective in preserving and enhancing bioactive compounds than thermal pasteurization. Consequently, the findings suggest the need for further investigations to assess the impacts of both thermal pasteurization and ultrasound technology on additional quality parameters of white grape juice.

Effect of electromagnetic field‐assisted freezing on improving the stability of lemon juice after thawing

AbstractThis study aims to reduce the production of flocculent material and stratification of lemon juice during freezing and thawing, using electric or magnetic fields to assist with the freezing of lemon juice. This study investigated the effect of 10–30 kV/cm electric field (EF) and 2–10 mT magnetic field (MF) on the quality of frozen lemon juice. Electromagnetic field treatment can shorten the freezing time and reduce its particle size, resulting in a lower polymer dispersion index and lower enzyme activity, thus improving its cloud stability. When the EF strength was 20 kV/cm and the MF strength was 6 mT, it resulted in the highest cloud stability, which increased by 15.50 and 16.95%, respectively. In addition, we studied the effect of electromagnetic fields on the physico‐chemical properties and bioactive components of lemon juice. The results showed that it did not affect its bioactive compounds activity and antioxidant activity, and did not cause loss of lemon juice flavor. The electromagnetic field treatment improved the quality of the juice and can be used as a potential novel processing technology for fruit juices.Practical ApplicationsThis study provides a simple and novel method to improve the stability of frozen lemon juice after thawing. The use of physical fields such as electric and magnetic field treatments to assist in freezing lemon juice improves the stability of lemon juice after thawing and provides a new method to improve the quality of fruit juice products.

Gut Microbiome and Metabolome Modulation by High-Hydrostatic-Pressure-Processed Tomato Juice.

High hydrostatic pressure (HHP) is a non-thermal pasteurization technology for the enhancement of food products' safety and quality. The components of tomato juice can be affected by HHP processing. Little is known about the effects of HHP-processed tomato juice on the gut microbiome and metabolism. Here, we performed high-throughput sequencing and metabolomics profiling to determine the critical differences in gut microbiota structure and metabolic profiles in mice administered with HHP-processed tomato juice. Tomato juice administration significantly increased the gut bacterial alpha diversity and the relative abundance of Bacteroides. The mice administered with HHP-processed tomato juice were characterized by the enrichment of Bacteroidetes, Alistieps, and Faecalibaculum compared with those administered with HTST-processed tomato juice. Moreover, HHP-processed tomato juice promoted SCFA levels, which were positively correlated with the enriched Alistieps. Our results show that HHP-processed tomato juice may drive healthy gut microbes and metabolites.

Gastric stability of bare and chitosan-fabricated ferritin and its bio-mineral: implication for potential dietary iron supplements.

Iron deficiency anaemia (IDA), the most widespread nutritional disorder, is a persistent global health issue affecting millions, especially in resource-limited geographies. Oral iron supplementation is usually the first choice for exogenous iron administration owing to its convenience, effectiveness and low cost. However, commercially available iron supplementations are often associated with oxidative stress, gastrointestinal side effects, infections and solubility issues. Herein, we aim to address these limitations by employing ferritin proteins-self-assembled nanocaged architectures functioning as a soluble cellular iron repository-as a non-toxic and biocompatible alternative. Our in vitro studies based on PAGE and TEM indicate that bare ferritin proteins are resistant to gastric conditions but their cage integrity is compromised under longer incubation periods and at higher concentrations of pepsin, which is a critical component of gastric juice. To ensure the safe delivery of encapsulated iron cargo, with minimal cage disintegration/degradation and iron leakage along the gastrointestinal tract, we fabricated the surface of ferritin with chitosan. Further, the stoichiometry and absorptivity of iron-chelator complexes at both gastric and circumneutral pH were estimated using Job's plot. Unlike bipyridyl, deferiprone exhibited pH dependency. In vitro kinetics was studied to evaluate iron release from bare and chitosan-fabricated ferritins employing both reductive (in the presence of ascorbate and bipyridyl) and non-reductive (direct chelation by deferiprone) pathways to determine their bio-mineral stabilities. Chitosan-decorated ferritin displayed superior cage integrity and iron retention capability over bare ferritin in simulated gastric fluid. The ability of ferritins to naturally facilitate controlled iron release in conjugation with enteric coating provided by chitosan may mitigate the aforementioned side effects and enhance iron absorption in the intestine. The results of the current study could pave the way for the development of an oral formulation based on ferritin-caged iron bio-mineral that can be a promising alternative for the treatment of IDA, offering better therapeutic outcomes.

Production and Characterization of Nata from Yam Bean Juice using Komagataeibacter nataicola TISTR 975

This study aimed to produce nata from Komagataeibacter nataicola TISTR 975 using yam bean juice as the fermentation substrate. The chemical components of yam bean juice and the physical characteristics of the produced yam bean nata were investigated. Yam bean nata were processed with juices from lemongrass (Cymbopogon citratus, Stapf; LG), Gac fruit (Momordica cochinchinensis Spreng; GF), and Centella (Centella asiatica; CA) and subsequently subjected to CIELAB value analysis, texture profile analysis (TPA), and sensory evaluation. The wet weight and thickness of yam bean nata were recorded as 130.36 ± 0.45 g and 9.64 ± 0.50 mm, respectively. The color analysis of yam bean nata revealed that the L* value slightly tended toward brightness; the a* value was negative, indicating green; and the b* value shifted toward blue. Upon processing, the yam bean nata with LG, GF, and CA exhibited an L* value tending toward white, an a* value indicating green, and a b* value indicating yellow. TPA results revealed a statistically significant disparity in hardness among the processed yam bean nata. Sensory attribute assessment indicated that processing the yam bean nata with LG, GF, and CA juices increased the liking score for overall acceptability.

Peracetic acid residues in orange juice can lead to a 5-vinylguaiacol-induced clove-like off-flavor via Baeyer-Villiger oxidation of hesperidin

A balanced flavor is a major quality attribute of orange juice. Formation of 4-vinylguaiacol during storage can lead to an undesirable clove-like off-flavor. However, clove-like off-flavors were occasionally reported despite low 4-vinylguaiacol concentrations, suggesting an alternative molecular background. Application of gas chromatography–olfactometry and aroma extract dilution analysis to an orange juice with a pronounced clove-like off-flavor resulted in the identification of 5-vinylguaiacol. The compound showed the same odor as 4-vinylguaiacol, but was previously unknown in orange juice. In five of six commercial orange juices with clove-like off-flavors, 5-vinylguaiacol was even more odor-active than 4-vinylguaiacol. Spiking and model studies suggested that 5-vinylguaiacol is formed during pasteurization from the natural orange juice component hesperidin and residual peracetic acid used as cleaning agent by a Baeyer-Villiger oxidation. An activity-guided screening approach confirmed the role of hesperidin as 5-vinylguaiacol precursor. In conclusion, peracetic acid should no longer be used in orange juice processing plants.

Antioxidant Edible Films Based on Pear Juice and Pregelatinized Cassava Starch: Effect of the Carbohydrate Profile at Different Degrees of Pear Ripeness.

Edible films based on fruit and vegetable purees combined with different food-grade biopolymeric binding agents (e.g., pectin, gelatin, starch, sodium alginate) are recognized as interesting packaging materials that benefit from the physical, mechanical, and barrier properties of biopolymers as well as the sensory and nutritional properties of purees. In the current contribution, edible antioxidant films based on pear juice and pregelatinized cassava starch were developed. In particular, the suitability of using pregelatinized cassava starch for the non-thermal production of these novel edible films was evaluated. In addition, the effects on the films' properties derived from the use of pear juice instead of the complete puree, from the content of juice used, and from the carbohydrate composition associated with the ripening of pears were all studied. The produced films were characterized in terms of their total polyphenol content, water sensitivity, and water barrier, optical, mechanical and antioxidant properties. Results showed that the use of pear juice leads to films with enhanced transparency compared with puree-based films, and that juice concentration and carbohydrate composition associated with the degree of fruit ripeness strongly govern the films' properties. Furthermore, the addition of pregelatinized cassava starch at room temperature discloses a significant and favorable impact on the cohesiveness, lightness, water resistance, and adhesiveness of the pear-juice-based films, which is mainly attributed to the effective interactions established between the starch macromolecules and the juice components.

Haskap Juicing Method Effects on Haskap Juice Quality

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.

Enhancement of physicochemical stability and reduction in enzyme and microbial activity of apple juice by hydrodynamic cavitation processing

Conventional thermally processed apple juices are nutritionally depleted because the heat sensitivity degrades the bioactive compounds that comprise them. This study proposed a non-thermal technique, hydrodynamic cavitation (HC), to preserve the nutritional content and prevent the loss of bioactive components in apple juice. In addition, the effect of hydrodynamic cavitation on the physicochemical, nutrition, and enzyme inactivation of freshly expressed apple juice has been studied. The design expert software has been used for process optimization, while fuzzy logic was applied for sensory. Hydrodynamic cavitation has been used on freshly extracted apple juice with inlet pressure in the range of (34.47–103.421 kPa) for a treatment time of (0–30 min). The apple juice was treated thermally at 90 °C for 2.5 min to compare the cavitation results. The settling of particles in the cavitation sample was 7%, which was lower than the heat-treated sample (10%) and untreated control sample (39%) and had a noticeable effect on the cloud value and stability of the apple juice. The HC treatment reduces the particle size of fresh apple juice from 8934.09 nm to 1112 nm, resulting in a homogenizing effect, a decrease in viscosity, and improved juice stability. Hydrodynamic cavitation reduced the antioxidant activity from 0.4987 mg GAE mL−1 (control) to 0.3951 mg GAE mL−1 yet retained better activity than the heat-treated apple juice (0.3489 ± 0.34 mg GAE mL−1) with microbial log reduction of 0.9 at 103.42 kPa treated for 30 min. After 15 days of storage at 4 °C, HC-treated juice had higher quality features and nutrient retention than heat-treated apple juice.

Effects of ultra-high pressure, thermal pasteurization, and ultra-high temperature sterilization on color and nutritional components of freshly-squeezed lettuce juice

The aim of this study was to evaluate the effects of ultra-high pressure (UHP, 600 MPa/2 min), thermal pasteurization (TP, 95 °C/1 min) and ultra-high temperature (UHT, 115 °C/5 s) sterilization on the color, sensory evaluation, microorganisms, physicochemical characteristics and nutritional components of freshly-squeezed lettuce juice (FLJ). Results showed that three sterilization methods demonstrated desirable inactivation effects on total aerobic bacteria, yeast and mold, and there were no significant changes in the main nutritional components, including ash, protein, carbohydrate and total dietary fiber. However, UHT and TP significantly affected the color of FLJ from bright green to light brown and made chlorophyll, β-carotene and vitamins (VE, VC, VK1, VB6, VB12, and folic acid) contents markedly decreased. By contrast, UHP maintained the original color, fresh-like sensory qualities, vitamins, and carotene of FLJ to the greatest extent. Our results provide a promising application of UHP in the large-scale processing of FLJ.

Changes in volatile and nutrient components of mango juice by different Lactic acid bacteria fermentation

This study investigated the changes in volatile and nutrient compounds of mango juice fermentation by lactic acid bacteria (LAB) (Lactobacillus plantarum NCU116, Lactobacillus acidophilus NCU402, and Lactobacillus casei NCU215). All strains grew well and L. plantarum NCU116 yielded the highest acidity and lactic acid content during fermentation. Meanwhile, L. plantarum NCU116 and L. acidophilus NCU402 fermentation significantly decreased L* and a* values. L. acidophilus NCU402 fermented mango showed the lowest levels of nitrite (0.01 μmol/g) and carotenoids (44.98 μg/g). Additionally, LAB fermentation enhanced aroma of mango juice by elevating alcoholic compounds and reducing terpenoids and aldehydes, with L. plantarum NCU116 demonstrating the most notable impact, increasing alcohol concentration from 5% to 17%. Correlation analysis revealed that key alcohols production was associated with amino acids, sugar, aldehydes, and terpenoids. According to the sensory analysis, the mango juice inoculated with L. casei NCU215 had the highest acceptability score. Thus, the type of LAB strains determined the nutrient component, volatile and sensory profile of mango juices and further research is needed to understand the fermentation mechanisms.