Characteristics and process optimization of rice snack (khao-tan) puffing by home microwave oven

Khao-tan is a popular Thai traditional glutinous rice snack that involves a deep frying process. Nowadays, consumers are concerned about the safety of fried food and its potential to contribute to obesity. Puffing using a home microwave oven is an alternative that is more convenient, requires a shorter processing time, has a lower cost, is healthy and environment-friendly. This research investigated the optimal processing conditions (initial moisture content [IMC], microwave power [MWP], and puffing time [PT]) to puff khao-tan from three rice varieties (sticky rice [SR], rice berry [RB], and black rice [BR]) using the microwave. Response surface methodology (the Box-Behnken technique) was applied. The process responses comprised puffing yield, expansion ratio, hardness, and yellowness. The results indicated that the optimized conditions for khao-tan were 10% IMC, 1,200 W MWP, and 25 s PT with overall desirability values of 0.733, 0.642, and 0.899 for SR, RB, and BR, respectively. Practical applications Recently, microwaves have become popular use in the food industry. This study provides a good technique to introduce microwave technology in the snack industry to puff a Thai traditional rice snack, namely, khao-tan using a home microwave oven. The optimized conditions can help with puffing khao-tan made with three varieties of rice (sticky rice, rice berry, and black rice) to achieve consumer acceptance in terms of product quality and a healthy product. This work can be applied commercially and on a small scale.