Raw milk has high nutritive value and is used as an important dietary supplement for humans. But, microbial contamination in milk has been a problem for era, while existing thermal technology often deteriorates the quality of milk and its valuable ingredients. Again, consumer demand for least processing technology without degradation of the product quality forced the scientist to develop novel methods relevant to the application of non-thermal technology which does not create any detrimental effect to the composition of milk are now being under scrutiny. One of the novel methods is plasma bubbling technique and is not yet examined for liquid foods like milk. In the present study, the plasma bubbling system was established for the decontamination of raw cow milk. The plasma bubbling was generated at voltage of 160V, for 5, 10 and 15 minutes (min) and was evaluated for microbial reduction at an air flow rate of 5 and 10 Litre/hour (L/h). It accounted for a maximum 1.33 log reduction for coliforms at 160V, flow rate of air was 10 L/h, for a 100mL of milk sample with 15 min exposure time, while for yeast the log reduction was 1.40. The plasma bubbled milk was analysed for its quality evaluation such as pH, acidity, colour and lactose content of milk. The value of pH was found to be 6.77 at 160V, 10L/h, 15 min and 100mL of sample volume while the control value of pH was 6.60. The findings from this study revealed that the atmospheric plasma bubbling system could be used for the pasteurisation of raw cow milk by reducing the microbial load without compromising milk quality. This work on novel atmospheric plasma bubbling is an initiative for the pasteurization of raw cow milk, which could have a potential impact on the food industry in future.

Raw cow milk being a highly nutritive but its contamination is one of the factors that has to be considered. Thermal treatment is generally adopted for decontamination of milk but at the same time it degrades the protein quality. Hence, there is a need for new treatment method with least processing technology to maintain the food quality. These challenges forced the scientist to introduce non-thermal technologies. The objective of the present study to elucidate the effect of optimized set up for plasma bubbling on casein protein and peptide with respect to raw cow milk. Structural characterization of casein was done using FTIR. The casein protein hydrophobicity was maintained well and Mascot result revealed a non-detrimental effect to α-s1casein peptide upon the treatment. Specifically, casein peptides are good source of ACE inhibitory peptides. While, ACE2 receptor is responsible for binding of SARS-CoV2. Therefore, this study implemented on most effective ACE inhibitory peptide (RYLGY) which was observed in Mascot analysis, for both control and treated sample arising from peak at 1267m/z in MALDI-TOF of α-s1-casein. The peptide was considered for in-silico docking approach against SARS-CoV2. Interestingly, ACE2-RBD-peptide complex showed good binding score, suggesting that the peptide molecule disturbed the complex formation.

The demand of consumers for naturality of food with minimal processing was forced to the scientists for the discovery of non-thermal plasma which is a new technology for the preservation and decontamination of food products. The present study was conducted for the scrutinization of microbial and physicochemical characteristics of plasma bubbled raw cow milk and an extensive comparison was observed for boiled raw cow milk, commercially (pasteurised and UHT) milk. Further, storage study (shelf-life) was done for the plasma bubbled raw cow milk and compared with raw cow milk sample (control). The bubbling of plasma was generated at a voltage of 200V, the flow rate of air 10 litres/hour (L/h) and applied to fresh cow milk for 5, 10, and 15 minutes (min) of time with a volume of 100 mL of the sample operated at room temperature. A declined in microbial cell was observed for coliform and yeast at 200V, 10L/h, 15 min time interval. The pH value of 15 min plasma bubble treated sample was increased significantly to 6.85. While, a slight decrease in value was noticed in total soluble solids (TSS) and titratable acid (TA) after exposure to plasma bubbling. Further, a nondetrimental effect was observed for the nutrient content of plasma bubbling of milk. The result indicates that plasma bubbling at generated at 200V, 10L/h,100mL,15 min treatment enhances the milk quality. However, plasma bubbling: based on indirect dielectric barrier discharge (DBD) may use as a successful decontamination technology without affecting the physicochemical properties which could have a future perspective on industrial food applications.

Cold plasma aims to decontaminate and maintain the naturality of the food. The present study discussed the application of novel plasma bubbling for raw milk pasteurization with different combinations of processing parameters such as voltage, flow rate of air, time interval and volume. The observation showed a decline in microbial load, with an increase in pH value up to 6.9 at optimised conditions (200 volts, the flow rate of air 10 Litres/hour, time 15 minutes and volume 100 mL). The optimized condition was observed was found to be appropriate and could be beneficial to the food industry.