Cold plasma processing of kiwifruit juice: Effect on physicochemical, nutritional, microstructure, rheological properties and sensory attributes.

This study aimed to compare the untreated, cold plasma (CP)-optimized (30 kV/5 mm/6.7 min), CP-extreme (30 kV/2 mm/10 min), and thermally treated (TT) (90 ℃/5 min) kiwifruit juices based on the physicochemical (pH, total soluble solids (TSS), titratable acidity (TA), total color change (ΔE)), physical (particle size and rheology), microstructure (optical microscope), bioactive compounds (polyphenol, ascorbic acid, and sugar compounds), and sensory characteristics of kiwifruit juice. The pH, TSS, and TA were not significantly affected in CP and TT juice, whereas the ΔE (6.52) of TT juice lies in the range of "greatly visible." The microstructure characteristics of juice significantly changed after CP and thermal treatment. The cell and tissue disruption in CP-extreme and thermally treated juice was more than CP-optimized. The particle size of juice decreased irrespective of treatment, but the span value of CP-optimized juice was the lowest. Further, the CP treatment showed a lower consistency index, apparent viscosity, and pseudoplasticity of juice than the thermal treatment. The CP-treated juice retained bioactive and nutritional attributes more than thermally treated juice. The CP-optimized, CP-extreme, and thermal treatment reduced the sucrose content by 54, 55, and 23%, while the fructose and glucose content were increased by 17, 12, & 93%, and 17, 11 & 99%, respectively. Among the CP-treated juice, CP-optimized (71.36 mg/100g) contained a higher amount of ascorbic acid than the CP-extreme (64.36 mg/100g). Based on the similarity values in the fuzzy logic analysis, the sensory attributes of CP-optimized treated juice were superior to CP-extreme and thermal treated. PRACTICAL APPLICATION: In this era, non-thermal processing techniques are trending for retaining the nutrition and stability of juice. The old plasma (CP)-treated kiwifruit juice had better nutritional, bioactive compounds, and sensory attributes than the thermally treated juice. Further, the CP-treated juice had higher flowability and lower viscosity, making it ideal for juice processing. The conclusions drawn suggest that CP processing is a better alternative for processing kiwifruit juice than thermal processing.

Effect of dielectric barrier discharge nonthermal plasma treatment on physicochemical, nutritional, and phytochemical quality attributes of pineapple [Ananas comosus (L.)] juice.

Forward feed multilayered perception and central composite rotatable design were used to model the nonthermal plasma (NTP) experimental data in artificial neural network (ANN) and response surface methodology, respectively. The ANN was found to be more accurate in modeling the experimental dataset. The NTP process parameters (voltage and time) were optimized for pineapple juice within the range of 25-45 kV and 120-900 s using an ANN coupled with the genetic algorithm (ANN-GA). After 176 generations of GA, the ANN-GA approach produced the optimal condition, 38 kV and 631 s, and caused the inactivation of peroxidase (POD) and bromelain by 87.24% and 51.04%, respectively. However, 100.32% of the overall antioxidant capacity and 89.96% of the ascorbic acid were maintained in the optimized sample with a total color change (ΔE) of less than 1.97 at all plasma treatment conditions. Based on optimal conditions, NTP provides a sufficient level of POD inactivation combined with excellent phenolic component extractability and high antioxidant retention. Furthermore, plasma treatment had an insignificant effect (p > 0.05) on the physicochemical attributes (pH, total soluble solid, and titratable acidity) of juice samples. From the intensity peak of the Fourier-transform infrared spectroscopy analysis, it was found that the sugar components and phenolic compounds of plasma-treated juice were effectively preserved compared to the thermal-treated juice.

Modeling of the inactivation kinetics of aerobic mesophiles and yeasts and molds natural microbiota in nonthermal plasma-treated pineapple (Ananas comosus) juice.

The nonthermal plasma (NTP) technology is a promising nonthermal technology that can be employed for pasteurization of fruit juice. The effect of NTP on the natural microbiota, namely, aerobic mesophiles (AM), and yeasts and molds (YM) in pineapple juice were examined in the experimental range of 25-45 kV up to 10 min treatment time. At an applied voltage of 45 kV, the AM and YM count reductions of 4.7 and 4.1 log cfu/mL were obtained at the end of the 14-min treatment. The inactivation kinetics of microbes were attempted to be explained using nonlinear models, including Weibull + tail, Geeraerd, log-logistic, Coroller, and Cerf. The residual population (Nres ) model parameter in the Geeraerd model explained the tailing behavior of microbes. Furthermore, the estimated values for the scale parameter and destruction rate constants were used to describe the sensitive and resistant percentages of the microbial population. According to statistical parameters (R2 : 0.978-0.999, RMSE: 0.034-0.277) and validation indicators (accuracy factor: 1.013-1.152, bias factor: 0.985-1.12), all models performed well. Akaike's theory was used to select the best-fit model, and the Coroller model was shown to be the most accurate one for AM and YM, exhibiting the lowest Akaike increment (Δi  = 0). PRACTICAL APPLICATION: Nonthermal plasma may be used as an alternate nonthermal process for this product in order to meet customer appeal for safe and nutritious juice with minimal processing. The goal of this work was to produce a nutritious and safe pineapple juice by using nonthermal processing.

Effect of cold plasma processing on physicochemical and nutritional quality attributes of kiwifruit juice.

Cold plasma treatment of kiwifruit juice was studied in the domain of 18-30 kV of voltage, 2-6 mm of juice depth, and 6-10 min of treatment time using the response surface methodology (RSM). The experimental design utilized was a central composite rotatable design. The effect of voltage, juice depth, and treatment time on the various responses, namely peroxidase activity, color, total phenolic content, ascorbic acid, total antioxidant activity, and total flavonoid content, was examined. While modeling, the artificial neural network (ANN) showed greater predictive capability than RSM as the coefficient of determination (R2 ) value of responses was greater in the case of ANN (0.9538-0.9996) than in RSM (0.9041-0.9853). The mean square error value was also less in the case of ANN than in RSM. The ANN was coupled with a genetic algorithm (GA) for optimization. The optimum condition obtained from ANN-GA was 30 kV, 5 mm, and 6.7 min, respectively.