Development, physical, and sensory characterization of extruded, indirectly puffed peanut-based snack products

Abstract

The goal of this research was to develop peanut-based snack products, known as third-generation snacks, using an extrusion process. Indirectly puffed extrudates were produced with a mixture of partially defatted peanut flour (12% fat) and rice flour using a co-rotating twin-screw extruder. The temperature profiles were 100, 120, 110, 95, and 80 ºC to prevent puffing of extrudates from feed zone to die, respectively. The extrudates were dried to obtain half-products (11-12% moisture). The half-products were expanded by deep-fat frying at 200 ºC for 35-40 sec. The quality of peanut-based snack products was determined by sensory evaluation, physical properties, cellular structure, and acoustic signal analysis.|A consumer acceptance test was conducted to determine the overall liking of snack products, and the optimum regions were identified using RSM. The Quantitative Descriptive Analysis (QDA) procedure was used to determine the characteristic sensory profiles of peanut-based snack products. The physical properties of snack products were significantly affected by peanut flour (30, 40, and 50%) followed by feed rate (4, 5, and 6 kg/hr) and screw speed (200, 300, and 400 rpm). Increasing peanut flour and feed rate resulted in lower degree of gelatinization and volume expansion ratio with higher bulk density. Response Surface Methodology (RSM) was used to determine the optimum area of formulations and extrusion conditions. Scanning Electron Microscopy (SEM) indicated that less expanded snack products have smaller cell size and thicker cell walls. The frequency ranges of acoustical signals produced by crushing snack products were identified from 4.5 kHz to 8.5 kHz by Fast Fourier Transformation (FFT). The lower peanut flour (30%) products produced more acoustic energy compared to the higher peanut flour (50%). The mechanical analysis revealed that the 30% peanut flour snack products were mechanically weaker than 50% peanut flour products.