Process modification for commercial production of rice kheer

Abstract

An investigation was carried out with an attempt to modify the conventional process for production of rice kheer. Mechanized in-line production system consisted of single stage scrapped surface heat exchanger (SSHE) in combination with conical process vat. SSHE was used for intensive heat treatment necessary for rapid concentration thus exploiting its high heat transfer characteristics and conical process vat (CPV) was employed for imparting desirable texture and flavour at low temperature heating for rice starch gelatinization. Trials for kheer production were conducted at different process parameter i.e. initial concentration of milk in SSHE (20%, 24%, 28%) and  conical vat steam pressure (1.5, 2.0, 2.5 kg/cm²). The effect of process parameters was studied on different responses viz acidity %, viscosity of milk serum, hardness of cooked rice grain, sensory attribute (9 point hedonic scale) and processing time. Results showed that process parameters had no effect on acidity. The lower hardness (2.82- 5.15 N) of cooked rice indicated proper cooking of rice. Viscosity of kheer was in the range of 0.17533 to  0.20133 Pa.s.  Kheer prepared from concentrating milk  upto 24 % TS in SSHE and processed in CPV at 2 kg/cm² was found best with maximum overall acceptability score.  Production time of kheer can be reduced from 63 min in conventional system to 33.5 min in mechanized inline system.