Obtaining ready-to-eat blue corn expanded snacks with anthocyanins using an extrusion process and response surface methodology.

Anayansi Escalante-Aburto,Roberto Gutiérrez-Dorado,Ignacio Morales-Rosas,Jaime López-Cervantes,Benjamín Ramírez-Wong,Juan Figueroa-Cárdenas,Patricia Torres-Chávez,Néstor Ponce-García,Jesús Barrón-Hoyos

doi:10.3390/molecules191221066

Abstract

Extrusion is an alternative technology for the production of nixtamalized products. The aim of this study was to obtain an expanded nixtamalized snack with whole blue corn and using the extrusion process, to preserve the highest possible total anthocyanin content, intense blue/purple coloration (color b) and the highest expansion index. A central composite experimental design was used. The extrusion process factors were: feed moisture (FM, 15%–23%), calcium hydroxide concentration (CHC, 0%–0.25%) and final extruder temperature (T, 110–150 °C). The chemical and physical properties evaluated in the extrudates were moisture content (MC, %), total anthocyanins (TA, mg·kg−1), pH, color (L, a, b) and expansion index (EI). ANOVA and surface response methodology were applied to evaluate the effects of the extrusion factors. FM and T significantly affected the response variables. An optimization step was performed by overlaying three contour plots to predict the best combination region. The extrudates were obtained under the following optimum factors: FM (%) = 16.94, CHC (%) = 0.095 and T (°C) = 141.89. The predicted extrusion processing factors were highly accurate, yielding an expanded nixtamalized snack with 158.87 mg·kg−1 TA (estimated: 160 mg·kg−1), an EI of 3.19 (estimated: 2.66), and color parameter b of −0.44 (estimated: 0.10).

Highlights

The energy density of ingested foods has increased globally; populations have become more urban, and the high consumption of products with large amounts of sugar, carbohydrates, dyes and saturated fats has been reported [1]
The aim of this study was to produce expanded nixtamalized expanded snacks using extrusion process with whole blue corn, and to apply response surface methodology to obtain a product with a high total anthocyanin content, an intense purple/blue coloration, and a high expansion index
The FM, in linear and quadratic terms, was the factor that most significantly affected all of the evaluations performed in the extrudates, except for the Total Anthocyanins (TA) determinations, where the quadratic term of

Summary

Introduction

The energy density of ingested foods has increased globally; populations have become more urban, and the high consumption of products with large amounts of sugar, carbohydrates, dyes and saturated fats has been reported [1]. There is an increase in the worldwide consumption of cereal-based foods, especially snack products. This market is expanding rapidly and will continue growing in the coming years. Snack foods are considered high energy density products, and they are directly related to promoting weight gain and to causing certain illnesses such as obesity and other related diseases (metabolic syndrome, cardiovascular events, hypertension, cancer) [1]. The EP has some advantages compared to the traditional nixtamalization process, including requiring less time and energy input and no production of water effluents (nejayote)

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