Effect of Hydrothermal Treatment on Cooking Quality Characteristics of Professor Jayashankar Telangana Agricultural University (PJTAU) Pre-release Rice Cultivars
Nazneen Begum *
Post Graduate and Research Centre, PJTAU, Rajendranagar, Hyderabad–500030, India.
T. Supraja
MFPI-Quality Control Laboratory, PJTAU, Rajendranagar, Hyderabad–500030, India.
B. Anila Kumari
Department of Foods and Nutrition, PG&RC, PJTAU, Rajendranagar, Hyderabad–500030, India.
Ch. Damodar Raju
Department of Genetics and Plant Breeding, Seed Research and Technology Centre, PJTAU, Rajendranagar, Hyderabad–500030, India.
*Author to whom correspondence should be addressed.
Abstract
Rice (Oryza sativa L.) cultivars exhibit considerable variation in cooking quality due to differences in their physicochemical and starch characteristics. The present study was undertaken to evaluate the cooking quality characteristics of selected Professor Jayashankar Telangana Agricultural University (PJTAU) pre-release rice cultivars before and after hydrothermal treatment. Eleven PJTAU pre-release rice cultivars, namely KNM 12368, KNM 12472, KNM 13555, KNM 7715, KNM 12510, KPS 10642, KPS 10631, KPS 10329, WGL 1380, WGL 1537 and RNR 35008, along with RNR 15048 and BPT 5204 as controls, were evaluated. Steaming was standardised using an autoclave at 0.5 and 1.0 kg/cm² gauge pressure for 5, 10 and 15 min. Based on milling performance, 1.0 kg/cm² gauge pressure for 5 min was selected for preparation of steamed samples. Raw and steamed rice were evaluated for cooking time, elongation ratio, water uptake ratio, alkali degradation, equivalent weight, gruel solid loss, volume expansion ratio and gelatinization temperature. Considerable variation was observed among PJTAU pre-release rice cultivars for all cooking quality parameters. Steaming generally reduced cooking time and gelatinization temperature, while increasing water uptake ratio and equivalent weight. Alkali degradation increased after steaming, indicating alterations in starch gelatinization behaviour. Gruel solid loss generally decreased following steaming, suggesting reduced leaching of solids during cooking. Elongation ratio and volume expansion ratio exhibited cultivar-dependent responses. The findings demonstrated that controlled hydrothermal treatment modified the cooking characteristics of rice, with the magnitude of changes varying among cultivars. Overall, steaming at 1.0 kg/cm² gauge pressure for 5 min showed potential for modifying the cooking quality of PJTAU pre-release rice cultivars.
Keywords: Rice cultivars, hydrothermal treatment, cooking quality, water uptake ratio, gelatinization temperature, gruel solid loss