44F-29 |
Acoustical and mechanical characterization on crispy peanut-based extrudate snacks |
I. CHOI1, R. D. Phillips1, Y. C. Hung1, and H. S. Jeong2. (1) Dept. of Food Science & Technology, Univ. of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, (2) Dept. of Food Science & Biotechnology, Chungbuk Provincial Univ., Okchon, 373-800, South Korea Snack foods are a significant part of America's diet and today's consumers are demanding a broader selection of snack foods. There are many peanut-based snacks having roasted peanut flavor available in the market, but an optimal process resulting in an expanded peanut product with a crispy texture have not been reported. The purpose of this study was to identify extrusion conditions to make half-products resulting in crispy peanut-based snacks as indicated by acoustical and mechanical evaluation of products. Mixtures of lightly roasted, partially defatted peanut flour (30-50%), rice flour and salt (2%) were extruded to obtain half-products at several screw speeds and feed rates. Half-products were dried and fried at 200°C for 30 sec. Snacks were compressed (Instron) and resulting sound recorded at a sampling rate of 44.1 kHz as digital data. The sound information in the frequency domain was obtained by using Fast Fourier Transformation (FFT). The sound intensity for crushing snacks increased slightly as screw speed increased from 200 to 400 rpm. The frequencies most represented in the spectrum occurred between 4000 and 7000 Hz. The 30% peanut flour mixture products which were run at 400 rpm screw speed and 4kg/hr feed rate produced the lowest amplitude of sound. Moreover, the area under the power spectral density curve for this snack generated a large signal to noise ratio of 52.74. This indicated that the maximum elastic energy was released as this sample was crushed. The force-deformational curve showed that the force of rupture drops with increasing screw speed, decreasing peanut level, and feed rate. The product with highest acoustic energy had the lowest shear strength (17N/g). These results indicate that crispy peanut-based snacks can be produced by extrusion cooking and frying, and that acoustical properties can provide valuable information in evaluating them.
Session 44F, Product Development
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