Impact of power ultrasound on the quality attributes of curd and its fermentation/gelation kinetics
Pintu Choudhary, Ashish Rawson
Abstract
Abstract In the present study, setting time, apparent viscosity and water‐holding capacity for Indian Curd was optimized by using central composite design, where process variable were amplitude level (20–100%, i.e., 11.6 μm–58 μm) and treatment time (5–30 min for treatment before inoculation and 5–15 min for treatment after inoculation). It was observed that ultrasound amplitude and treatment time significantly affected the response variables. The optimum condition for ultrasound treatment before inoculation was identified as 69.43% amplitude and 14.12 min treatment time for minimum curd setting time 5.46 hr., maximum apparent viscosity 24.53 Pa.s and maximum water‐holding capacity 75.79%. The optimum condition for ultrasound treatment after inoculation was identified as 51.46% amplitude level and 9.74 min treatment time for minimum curd setting time 3.40 hr., maximum apparent viscosity 12.12 Pa.s and maximum water‐holding capacity 66.69%. Fermentation kinetics was studied, using Weibull model for optimized condition obtained from RSM. It was found that ultrasound significantly affected the kinetic parameter, that is, rate constant (K) which was maximum for sample treated with ultrasound after inoculation followed by the sample treated with ultrasound before inoculation and control sample ( R 2 > 80%). Practical Applications This result has a significant potential to be used in the dairy industry for curd formation, as ultrasound pretreatment can significantly decrease the curd fermentation/gelation time, save time and increase the production efficiency. Consumption of Curd is correlated to improved gut microflora which eventually leads to good health. Hence curd is an important diet across the globe. Industrial production of curd generally requires 5 hrs or more for fermentation. In this regard present study identified and confirmed a novel method of curd processing using power ultrasound treatment which could not only improve the quality of curd but also accelerate the rate of fermentation for curd formation. Further this study has established a kinetic model for fermentation of curd, which has the potential to be utilized by dairy industry for curd production, thus saving time and increasing the production efficiency and profit.