Effect of storage and reheating on textural properties of rice in dairy dessert as related to its pasting properties and microstructure

Abstract

Kheer, a milk-rice dessert akin to “rice pudding” or “milk rice” or “riz au lait” or “pudin de arroz” is prepared by cooking rice in milk till a cream-like to thick, pudding-like consistency. Upon refrigerated storage of kheer, the rice grains tend to become tough, render the product coarse and unacceptable presumably because of retrogradation of the starch. Kheer prepared from Basmati or Parimal rice were stored at 6 °C and their textural properties were monitored. The impact of in-pouch reheating on softening of rice grains were studied simultaneously. As determined instrumentally and sensorily, the rice grains became progressively harder (1.05–2.25 N and 3.19 to 6.63 N for Basmati and Parimal rice, respectively) and coarser during the 4-week refrigerated storage. Reheating of kheer (50, 60, 70 or 80 °C) resulted in appreciable recovery of the textural attributes of kheer in terms of hardness and coarseness. However, the reheating temperature had little impact on the grain softening. Further, the coarseness caused by grain-hardening in the cold-stored product could not be reversed to the same extent as the grain hardness. Scanning electron microscopy revealed the presence of crystals of retrograded amylose, in rice as well as in serum.