Impact of pulsed electric field treated milk on quality of paneer and khoa

Abstract

The present work was undertaken to investigate the feasibility of pre-treatment of raw milk with Pulse Electric Field (PEF) treatment before its entry into the processing chain. A custom-designed and fabricated PEF applicator was used for the non-thermal treatment protocol. Raw milk was treated under three treatment protocols, viz., conventionally heat treatment (CHT), PEF treated milk subjected to conventional heat treatment (PT-CHT) and PEF treatment (PT). For the PT protocol, milk was subjected to high voltage (55 kV) square wave of pulse width 900 µs, for 100 s at a frequency of 90 Hz. The treated milk was then converted to two popular products, namely and paneer and khoa, which were evaluated for its physico-chemical, microbiological, sensory quality and shelf stability. Since khoa is a heat desiccated product, it was evaluated only against PT-CHT and CHT treatments. It was observed that PT treatment resulted in paneer with softer body with higher whiteness index, compared to other experimental samples. The PT treatment did not affect the product acceptability and the product had a shelf stability of 12 days under refrigeration, as against 16 days for CHT and PT-CHT treatment. The treatment protocols for milk did not significantly affect the quality and shelf life of khoa. Thus, there is wide future scope to used pulsed electric fields treatment synergistically with conventional heat treatment for inactivation of microorganisms, with better retention of nutritional and physical properties of product which has potential to save considerable amount of energy and time during processing of product.

Pulsed electric field processing in the dairy sector: A review of applications, quality impact and implementation challenges

“…Preeti et al . (2022) observed a 3.97‐log of total bacterial count in the paneer samples given a PEF treatment (field strength = 55 kV cm −1 for 50 s, pulse width = 900 and f = 90 Hz, no pre‐heating). While in the samples where PEF treatment was assisted with heat treatment up to 95 °C the log count of total bacteria was 3.48.…”

“…Preeti et al . (2023) reported the improved viscosity index of the curd treated with PEF (field strength = 55 kV cm −1 , frequency = 90 Hz (bipolar square waves), pulse width of 900 μs and treatment time of 100 s).…”

“…Along with enhanced flavour, the textural properties, such as the springiness of cheese can also be improved through the treatment (Upadhyay et al ., 2019). PEF‐treated milk (field strength = 55 kV cm −1 , frequency = 90 Hz (bipolar square waves), pulse width of 900 μs and treatment time of 100 s) was used for the preparation of paneer, which had a better body, texture, and whiter colour than paneer made from untreated milk (Preeti et al ., 2022). However, additional research is required to comprehensively comprehend the PEF influence on the sensorial parameters of milk and its products.…”

“…Preeti et al . (2023) reported the poorer sensory scores of the curd developed with PEF‐treated milk (field strength = 55 kV cm −1 , frequency = 90 Hz (bipolar square waves), pulse width of 900 μs and treatment time of 100 s). It was attributed to the negative impact on the texture of the curd due to the increased acidity of the curd resulting in the softer texture and increased syneresis.…”

“…Preeti et al . (2023) have observed an elevated whiteness index of the paneer produced from PEF‐treated milk (field strength = 55 kV cm −1 , frequency = 90 Hz (bipolar square waves), pulse width of 900 μs and treatment time of 100 s). Overall, due to variations in process variables such as field strength, geometry of the waves, treatment time, and frequency employed, the alteration in the milk and its products' sensorial properties varied widely and yet to be completely understood (Soltanzadeh et al ., 2022).…”