Effects of Pectinase Pre-Treatment on the Physicochemical Properties, Bioactive Compounds, and Volatile Components of Juices from Different Cultivars of Guava

Probiotic lychee wine fermented by Saccharomyces boulardii: addition influence of yerba mate on physicochemical and sensory characteristics

Lychee (LHF) and lychee with yerba mate (LMF) wines were developed in two fermentation stages by the probiotic yeast Saccharomyces boulardii. The physicochemical and sensory characteristics of the wines, as well as the total phenolic compounds (TPCs), methylxanthines, phenolic acids, flavonoids and antioxidant activity (AA), were determined. Yeast showed viability > 6.31 log CFU mL- 1 in the LHF and LMF wines at the end of preparation, demonstrating the probiotic potential of the proposed beverages. S. boulardii metabolizes the sugars present in beverages, generating ethanol and CO2. LHF wines had a higher content of vitamin C and a lighter color, with alcoholic, sweet and sweet fruit flavours. The yerba mate provided greater AA, TPC and methylxanthine contents; phenolic acid and flavonoid levels; brown, ocher, and yellowish colours; honey and dark colours; fermented aroma; yerba mate and fermented flavour; bitter taste and aftertaste; and greater viscosity in the mouth in the LMF wines. Fermented Lychee wines were generally more sensorially accepted. A greater preference was observed for LHF wine with a second fermentation for 15 days at 10 °C.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-06089-8.

Production and Characterization of Pectinase Through Solid-State Fermentation of Orange Peels by a Mutant Yeast Strain

Pectinases hydrolyze pectin in plant biomass and are commonly used in the fruit juice industry. In this study, pectinase produced by a mutant yeast strain, Geotrichum candidum AHC1, was characterized and used to clarify the orange juice. The strain AHC1 produced 76.08 IU mL-1 pectinase after fermenting orange peel powder under solid-state conditions. This yield was several folds higher than G. candidum AA15 (wild type) and Saccharomyces cerevisiae MK-157. Moreover, S. cerevisiae MK-157, G. candidum AA15, and G. candidum AHC1 produced 42.62, 58.28, and 75.28 IU mL-1 pectinase, respectively, under submerged fermentation. Consequently, pectinase from AHC1 was characterized by using a central composite design. Results indicated that pectinase from AHC1 exhibited maximum activity at 35°C, 16.47 min reaction time, 1.89% substrate concentration, and pH 5.4. Under optimized conditions, the preparation exhibited 87 IU mL-1 pectinase activity, which was correlated with the predicted value (95.13 IU mL-1). Furthermore, K m of the crude pectinase (16 mg mL-1) was found to be greater in comparison to the purified pectinase, demonstrating its high affinity to pectin. The treatment of orange juice with pectinase resulted in increased yield and clarity within 30 min. This study provides prospects for a citrus circular bioeconomy by utilizing orange peels to produce pectinase and subsequently using pectinase to clarify orange juice.

Magnetic Janus SiO2 nanoparticles immobilized protease mutant T70I as a novel clarification agent for juice processing

The juice processing industry offers several benefits, including promoting health and wellness through the delivery of beverages rich in nutrients. Nonetheless, the industry encounters significant challenges regarding new technologies for processing and preservation given that they can be costly and labor-intensive. In this study, magnetic Janus silica (SiO2) nanoparticle which offers multifunctionality and high stability was synthesized and subsequently immobilized with a protease mutant T70I (T70I@MSNs) to serve as a clarifying agent in juice. The optimal conditions for the protease immobilized with SiO2 nanoparticles showed superior tolerance and stability at pH 5 and 65 °C. Box-Behnken Design revealed optimizing conditions of 60 min, 50 °C and 0.2 % enzyme concentration which significantly influenced the clarification of the juice samples. Immobilized T70I@MSNs decreased >70 % of juice turbidity while maintaining about 78 % of enzyme activity after 7 consecutive cycles of reuse. Notably, T70I@MSN treatment enhanced certain volatile components by increasing alcohol and ester production, while changes in surface microstructure and functional groups were observed. This study highlights the significant improvement of magnetic Janus SiO2 nanoparticles immobilized proteases in the clarification of juice against haze and undesirable properties, thereby offering a notable contribution to the juice processing industry.

Immobilization of purified pectinase from Aspergillus nidulans on chitosan and alginate beads for biotechnological applications

BACKGROUND

Because the process is cost-effective, microbial pectinase is used in juice clearing. The isolation, immobilization, and characterization of pectinase from Aspergillus nidulans (Eidam) G. Winter (AUMC No. 7147) were therefore the focus of the current investigation.

RESULTS

Ammonium sulphate (85%), DEAE-cellulose, and Sephadex G-200 were used to purify the enzyme. With a yield of 30.4%, the final specific activity was 400 units mg-1 protein and 125-fold purification. Using SDS-PAGE to validate the purification of the pectinase, a single band showing the homogeneity of the purified pectinase with a molecular weight of 50 kD was found. Chitosan and calcium alginate both effectively immobilized pectinase, with immobilization efficiencies of 85.7 and 69.4%, respectively. At 50, 55, 60, and 65 °C, the thermostability of both free and chitosan-immobilized pectinase was examined. The free and chitosan-immobilized enzymes had half-lives (t1/2) of 23.83 and 28.64 min at 65 °C, and their Kd values were 0.0291 and 0.0242 min-1, respectively. In addition, the Z values were 44.6 and 31.54 °C, while the D values were 79.2 and 95.1 min. Compared to the untreated one, the orange, mango, and pineapple juices treated with immobilized pure pectinase showed greater clarity. Following treatment with pure pectinase, the fruit juice's 1, 1-diphenyl-2-picrylhydrazyl and 2, 2'-azino-bis 3-ethylbenzothiazoline-6-sulfonate scavenging activities increased. Following treatment with pure pectinase, the amounts of total phenolics and total flavonoids increased.

CONCLUSION

The procedure is deemed cost-effective in the food industry because the strong affinity of fungal pectinase for pectin. The investigated pectinase supported its usage in the food industry by being able to clear orange, mango, and pineapple juices.

Enhancing drying characteristics and quality of fruits and vegetables using biochemical drying improvers: A comprehensive review

Traditional drying is a highly energy-intensive process, accounting for approximately 15% of total manufacturing cost, it often resulting in reduced product quality due to low drying efficiency. Biological and chemical agents, referred to as biochemical drying improvers, are employed as pretreatments to enhance both drying characteristics and quality attributes of fruits and vegetables. This article provides a thorough examination of various biochemical drying improvers (including enzymes, microorganisms, edible film coatings, ethanol, organic acids, hyperosmotic solutions, ethyl oleate alkaline solutions, sulfites, cold plasma, carbon dioxide, ozone, inorganic alkaline agents, and inorganic salts) and their effects on improving the drying processes of fruits and vegetables. Additionally, it introduces physical drying improvers (including ultrasonic, pulsed electric field, vacuum, and others) to enhance the effects of biochemical drying improvers. Pretreatment with biochemical agents not only significantly enhances drying characteristics but also preserves or enhances the color, texture, and bioactive compound content of the dried products. Meanwhile, physical drying improvers reduce moisture diffusion resistance through physical modifications of the food materials, thus complementing biochemical drying improvers. This integrated approach mitigates the energy consumption and quality degradation typically associated with traditional drying methods. Overall, this review examines the role of biochemical agents in enhancing the drying characteristics and quality of fruits and vegetables, offering a comprehensive strategy for energy conservation and quality improvement.

Homologous expression of Aspergillus niger α-L-rhamnosidase and its application in enzymatic debittering of Ougan juice

The α-L-rhamnosidase (rha1) gene was homologously expressed in Aspergillus niger strains CCTCC 206047 and CCTCC 206047ΔpyrG, using hygromycin B and auxotrophic as selection markers. The engineered A. niger strains RHA001-1 and RHA003-1 were screened, yielding α-L-rhamnosidase activities of 20.81 ± 0.56 U/mL and 15.35 ± 0.87 U/mL, respectively. The copy numbers of the rha1 gene in strains RHA001-1 and RHA003-1 were found to be 18 and 14, respectively. Correlation analysis between copy number and enzyme activity in the A. niger strains revealed that α-L-rhamnosidase activity increased with the copy number of the rha1 gene. Recombinant α-L-rhamnosidase was utilized for the enzymatic debittering of Ougan juice, and its process conditions were optimized. Furthermore, the primary bitter substance neohesperidin (2.22 g/L) in Ougan juice was converted into hesperetin 7-O-glucoside (1.47 g/L) and hesperidin (0.143 g/L). This study presents a novel approach for the production of food-grade α-L-rhamnosidase and establishes a technical foundation for its application in the beverage industry.

Identification of Enzymes and Their Key Action Sites for Histamine Degradation in Mulberry Fruit Wine by Lactiplantibacillus plantarum

In this study, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and multicopper oxidase (MCO) of Lactiplantibacillus plantarum W155 with histamine degradation ability were expressed. The mulberry fruit wine (MFW) histamine degradation abilities of GAPDH and MCO were 20.81% and 37.67%, respectively. Compared with the control group, the MFW treated by GAPDH showed higher total phenolic (1.17 g GAE/L) and total flavonoid (0.31 g RE/L) contents, while MFW treated by MCO presented similar total phenolic (1.00 g GAE/L) and total flavonoid (0.29 g RE/L) concentrations. Furthermore, the optimal pH and temperature of GAPDH were 6.0 and 40 °C, respectively, while the optimal pH and temperature of MCO were 3.0 and 50 °C, respectively. Meanwhile, the key action sites for histamine degradation of GAPDH and MCO were minded via homology modeling, molecular docking, and site-directed mutagenesis. Val209 and Ile290 were confirmed as the key action sites for GAPDH, while Qln402 and Leu420 were the pivotal action sites for MCO. Above findings indicated that both GAPDH and MCO of L. plantarum W155 could be used to control the histamine of MFW, and the key action sites of these two enzymes could be used as targets for their subsequent modification.

Production, Purification, and Characterization of a Cellulase from Paenibacillus elgii

Cellulases are one of the most essential natural factors for cellulose degradation and, thus, have attracted significant interest for various applications. In this study, a cellulase from Paenibacillus elgii TKU051 was produced, purified, and characterized. The ideal fermentation conditions for cellulase productivity were 2% carboxymethyl cellulose (CMC) as the growth substrate, pH = 8, temperature of 31 °C, and 4 days of culturing. Accordingly, a 45 kDa cellulase (PeCel) was successfully purified in a single step using a High Q column with a recovery yield of 35% and purification of 42.2-fold. PeCel has an optimal activity at pH 6 and a temperature of 60 °C. The activity of cellulase was significantly inhibited by Cu2+ and enhanced by Mn2+. The PeCel-catalyzed products of the CMC hydrolysis were analyzed by high-performance liquid chromatography, which revealed chitobiose and chitotriose as the major products. Finally, the clarity of apple juice was enhanced when treated with PeCel.

Effect of Novel Processing Techniques on the Carotenoid Release during the Production of Red Guava Juice

Red guava, distinguished by its elevated lycopene content, emerges as a promising natural source of carotenoids. This study systematically evaluates the impact of diverse processing techniques on the efficient release of carotenoids. The primary objective is to facilitate the transfer of carotenoids into the juice fraction, yielding carotenoid-enriched juice seamlessly integrable into aqueous-based food matrices. The untreated guava puree exhibited a modest release of carotenoids, with only 66.26% of β-carotene and 57.08% of lycopene reaching the juice. Contrastly, both high-pressure homogenization (HPH) at 25 MPa and enzyme (EM) treatment significantly enhanced carotenoid release efficiency (p < 0.05), while high hydrostatic pressure (HHP) at 400 MPa and pulsed electric field (PEF) of 4 kV/cm did not (p > 0.05). Notably, HPH demonstrated the most substantial release effect, with β-carotene and lycopene reaching 90.78% and 73.85%, respectively. However, the stability of EM-treated samples was relatively poor, evident in a zeta-potential value of -6.51 mV observed in the juice. Correlation analysis highlighted the interactions between pectin and carotenoids likely a key factor influencing the stable dissolution or dispersion of carotenoids in the aqueous phase. The findings underscore HPH as a potent tool for obtaining carotenoid-enriched guava juice, positioning it as a desirable ingredient for clean-label foods.