Effects of thermosonication process on inactivation ofEscherichia coliandSaccharomyces cerevisiaeand its survival kinetics modeling in khoonphal (Haematocarpus validus) juice to extend its shelf life

Application of thermosonication for guava juice processing: Impacts on bioactive, microbial, enzymatic and quality attributes

The present work explores different conditions of thermosonication (TS) processing that would ensure microbiological and enzymatic safety for guava juice while simultaneously maximizing the preservation of its quality attributes. The guava juice was subjected to TS treatment (frequency: 40 kHz; power: 200 W; Temperature: 40, 60, and 80 °C; Time: 2, 6 and 10 min) and was compared with fresh and pasteurized (90 °C/60 s) juice samples. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as total soluble solids (TSS), pH, titratable acidity, cloud value, color attributes, total phenolic contents, total flavonoid contents, antioxidant activity, ascorbic acid levels, enzymatic, microbiological, and sensory properties. The thermosonicated and pasteurized samples showed no significant (p > 0.05) changes in pH, total soluble solids, and titratable acidity. TS improved the cloud value and color attributes. Furthermore, TS enhanced total phenols (10 to17%), flavonoids (5 to 25%), antioxidant activity (10.45% to 14.55%) and retention of ascorbic acid (61.98-83.32%) relative to control. Thermosonicated sample at 80 °C/10 min gives the maximum inactivation of Pectin methyl esterase (PME), Peroxidase (POD) and Polyphenol oxidase (PPO) enzymes. While both thermosonication and pasteurization drastically decreased the microbial count to undetectable levels, only TS exhibited modest improvement in sensory qualities. The results demonstrated that TS can enhance the overall safety, quality, and commercial viability of guava juice as a practical substitute to pasteurization.

Effect of thermosonication on bioactive compounds, enzymatic and microbiological inactivation in nectar with strawberry by-products

The aim of this study was to evaluate whether the addition of strawberry by-products (pulp and achene) and thermosonication offers a nectar with a potential contribution of health and safety benefits. Strawberry nectar with 0, 10 and 20% of strawberry by-products (SB) was subjected to thermosonication (24 kHz) at 70 and 80% for 8 min at 50 °C. Total soluble solids, pH, polyphenol oxidase (PO) and pectin methylesterase (PME) activities, total soluble phenols (TSP), ascorbic acid (AA), anthocyanins and antioxidant capacity (AOX) were evaluated. Microbiological reduction and inactivation of Escherichia coli was also determined. A limited activity was observed in PO and PME related to the SB percentage added. TSP, AA, anthocyanins, and AOX were increased due to the different percentages of SB added to the nectar. A reduction of aerobic mesophiles (1.28 Log CFU/mL), molds and yeast counts (1.23 Log CFU/mL) were achieved by thermosonication. E. coli inactivation was approximately 1 log CFU/mL in 20% SB nectar at 80% amplitude, 8 min at 50 °C, but increased during storage at 6 °C (0.915-5.86 Log CFU/mL). Thermosonication showed the possibility of employing strawberry by-products in nectars, improving the use of agro-industrial residues by non-thermal technologies.

Alginate and β-lactoglobulin matrix as wall materials for encapsulation of polyphenols to improve efficiency and stability

The present study aimed at developing novel encapsulate materials of calcium-alginate and β-lactoglobulin complex for polyphenols using the jet-flow nozzle vibration method. Encapsulated microbeads were characterized using SEM, FTIR, DSC, and MSI. The encapsulation efficiency of the microbeads varied depending upon the coating material in the range of 74.17–84.87%. Calcium-alginate-β-lactoglobulin microbeads (CABM) exhibited a smooth surface and uniform shape with an average particle size of 1053.73 nm. CABM also showed better thermal and storage stabilities as compared to calcium alginate microbeads. The CABM resulted in excellent target release of polyphenols (84%) in the intestine, which was more than 3-fold the bio-accessibility offered by free polyphenol powder. Further study on individual phenolic acids after simulated in-vitro digestion (SIVD), photo-oxidative and osmotic stress revealed that CABM significantly retained a higher amount of polyphenols and exhibited improved antioxidant capacity after SIVD environment, and may have high industrial application for nutraceutical production.

Ultrasound assisted modulation of yeast growth and inactivation kinetics

The yeast Saccharomyces cerevisiae is well known for its application in the food industry for the purpose of developing fermented food. The ultrasound (US) technology offer a wide range of applications for the food industry, including the enhancement of fermentation rates and inactivation of microbial cells. However, a better understanding and standardization of this technology is still required to ensure the scaling-up process. This study investigated the effect of the US technology on the growth of S. cerevisiae using frequencies of 20, 25, 45 and 130 kHz, treatment periods from 2 to 30 min. Furthermore, yeast kinetics subjected to US treatments were evaluated using modelling tools and scanning electron microscopy (SEM) analysis to explore the impact of sonication on yeast cells. Yeast growth was monitored after different US treatments plotting optical density (OD) at 660 nm for 24 h at 30 ⁰C. Growth curves were fitted using models of modified Gompertz and Scale-Free which showed good parameters of the fit. In particular, US frequencies of 45 and 130 kHz did not have a disruptive effect in lag phase and growth rate of the yeast populations, unlike the frequency of 20 kHz. Moreover, inactivation curves of yeast cells obtained after exposure to 20 and 25 kHz also observed the best fit using the Weibull model. US frequency of 20 kHz achieved significant reductions of 1.3 log cfu/mL in yeast concentration and also induced important cell damage on the external structures of S. cerevisiae. In conclusion, the present study demonstrated the significant effect of applying different US frequencies on the yeast growth for potential application in the food industry.

Application of a 360-Degree Radiation Thermosonication Technology for the Inactivation of Staphylococcus aureus in Milk

Milk is easy to be contaminated by microorganisms due to its abundant nutrients. In this study, a 360-degree radiation thermosonication (TS) system was developed and utilized for the inactivation of Staphylococcus aureus in milk. The 360-degree radiation TS system-induced inactivation kinetics of S. aureus was fitted best by the Weibull model compared with biphasic and linear models. The treatment time, the exposure temperature, and the applied ultrasound power was found to affect the bactericidal efficacy of the 360-degree radiation TS system. Additionally, the TS condition of 200 W and 63°C for 7.5 min was successfully applied to achieve complete microbial inactivation (under the limit of detection value) in raw milk. The treatment of 360-degree radiation TS can enhance the zeta potential and decrease the average particle size of milk. It also exhibited better retainment of the proteins in milk compared with the ultrahigh temperature and conventional pasteurization processing. Therefore, the 360-degree radiation TS system developed in this study can be used as an alternative technology to assure the microbiological safety and retain the quality of milk, and the Weibull model could be applied for the prediction of the inactivation levels after exposure to this technology.

In vitro cytoprotective activity of cyanidin 3-glucoside extracts from Haematocarpus validus pomace on streptozotocin induced oxidative damage in pancreatic β-cells

Cyanidin-3-glucoside (C3Ghv) compounds were purified and isolated from the anthocyanins extract of Haematocarpus validus. C3Ghv were studied for antioxidant and cytoprotective properties on pancreatic β-cells of rat insulinoma cells (RINm5F) against the oxidative stress induced by streptozotocin (STZ). The exposure of RINm5F cells to C3Ghv at concentration of 100 and 200 μg/mL for 24 h reduced 10% and 23% cell viability, respectively, as compared to control cells. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) increased the cell viability by 29% as compared to control, on being treated with STZ (10 mM) for 24 h. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) for 24 h followed by exposure to STZ (10 mM) for 1 h decreased the generation of reactive oxygen species (ROS) by 57%, generation of nitric oxide by 22.8%, generation of malondialdehyde (MDA) by 32%, the production of p-ERK ½ by 83%, p-JNK by 82.6%, p-MEK by 57%, and p-p38 MAPK by 64%. The C3Ghv treatment also decreased the ratio of apoptotic proteins Bax to Bcl-2 by 61%, and improved the M2 phase of cell cycle by 75% as compared to STZ treated cells. The overall results suggest that C3Ghv protects pancreatic β-cells against oxidative stress-induced apoptosis, thereby implicating the significant role of C3Ghv as an antidiabetic agent.

GC-HRMS screening of bioactive compounds responsible for antimicrobial and antioxidant activities of blood fruit (Haematocarpus validus Bakh. F. Ex Forman) of North-East India

The aims of this study are to evaluate phytochemical composition, antimicrobial and antioxidant activities of different solvent-assisted blood fruit pulp extracts. The extracts of blood fruit were prepared with various solvents namely, water, ethyl acetate, methanol and acetone. These extracts were divided into two groups, first group of extract were thermosonicated (treated) and the second group were not exposed to thermosonication (untreated). The sample extracts were then evaluated for their antimicrobial properties against various microorganisms. The results revealed that the antimicrobial activity of thermosonicated ethyl acetate extracts at 12 mg/mL concentration exhibited the highest inhibition zone of 19.4 mm against Staphylococcus aureus. The phenolic content of ethyl acetate extract was found to be the highest as compared to that of other solvent extracts and the values were 1508.08 and 1478.34 mg GAE/100 g for treated and untreated samples, respectively. The treated ethyl acetate extract antioxidative activity by DPPH, ORAC, ABTS, and FRAP assay were 1627.68, 2119.82, 938.11, and 2360.18 µmol TE/g, respectively. The minimum bactericidal concentration (MBC - 1.5 mg/mL) against the selected foodborne pathogens was obtained with thermosonicated ethyl acetate blood fruit extract. In the present study, it was observed that the thermosonicated ethyl acetate extract exhibits maximum antioxidant and antimicrobial activities than any other examined solvent extracts. The major bioactive volatile compounds found in treated ethyl acetate extracts were 2-bromotetradecane, tetracosane, heptadecane, eicosane and palmitic acid. These bioactive compounds can be utilizable for the development of functional, nutraceutical and pharmacological products.

Process optimization for the production of blood fruit powder by spray drying technique and its quality evaluation

Blood fruit (Haematocarpus validus) has important bioactive compounds, antioxidant properties and some essential minerals, which plays an essential part in human nutrition and traditional medicine for treating arthritis, jaundice, hypertension, cancer, etc. This work was conducted to optimize the parameters of spray drying process for production of blood fruit juice powder and its quality was compared with freeze dried and tray dried powder. It was observed that powder produced by spray drying techniques resulted in higher yield, solubility and better retention of resveratrol content and was considered to be of superior quality, having a higher degree of reconstitution ratio as compared to powders produced by freeze and tray drying techniques. High performance liquid chromatography study of blood fruit powder showed the presence of resveratrol and other phenolic compounds. Scanning electron microscope was used to study the surface morphology and it revealed that spray-dried powder has uniformity in shape and size as compared to freeze dried and tray dried powder. The present investigation indicated that spray drying results in better, superior quality powders that are easier for packaging, transportation, having better shelf life.