Optimisation of the Extrusion Process through a Response Surface Methodology for Improvement of the Physical Properties and Nutritional Components of Whole Black-Grained Wheat Flour.

Yuxiu Liu,Shuhua Huang,Miaomiao Liu,Zhengmao Zhang

doi:10.3390/foods10020437

Yuxiu Liu, Shuhua Huang + Show 2 more

Open Access

https://doi.org/10.3390/foods10020437

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Abstract

Chronic undernourishment affects billions of people. The development of whole-grain food with high nutritional quality may provide a valuable solution to nutritional security. Black-grained wheat (BGW), as a rich source of protein and micronutrients, is a good raw material for value-added products. The objectives of this study were to investigate the effects of barrel temperature, feed moisture content, and feed rate on the physical properties and nutritional components of whole BGW flour extrudates and to optimise their processing conditions by using the response surface methodology. The increasing barrel temperature, feed moisture content, and feed rate affected the specific volume, expansion ratio, hardness, fracturability, water absorption index (WAI), water solubility index (WSI), and total starch content of the extrudates, but did not significantly affect the content of protein, ash, iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn). The extruded wheat flour had a significantly higher content of Fe and Cu, and a lower total starch content than the unextruded flour under extrusion conditions. A significantly higher content of protein, ash, Zn, Cu, and Mn, and a significantly lower total starch content were found in the extruded and unextruded flours made of whole BGW than in those made of whole white-grained wheat. According to the significance of the regression coefficients of the quadratic polynomial model, the optimum extrusion parameters were as follows: a barrel temperature of 145.63 °C, feed moisture content of 19.56%, and feed rate of 40.64 g·min−1 in terms of the maximum specific volume, expansion ratio, fracturability, WAI and WSI, and the minimum hardness. These results may be used by food manufacturers to successfully develop extruded products from whole BGW flour, meeting consumer demands and needs.

Highlights

The nutritional requirements for humans mainly depend on plant-based food, such as that made from the edible portion of staple crops [1]
The specific volume and the expansion ratio of the extrudates were significantly decreased with an increase in the barrel temperature (α = 0.01), indicating that the increasing barrel temperature had an adverse effect on the specific volume and the expansion ratio of the whole-wheat flour extrudates
The increase in the water solubility index (WSI) of the extrudates with increasing barrel temperature was attributed to the increase in soluble components with starch melting by extrusion [53,54]

Summary

Introduction

The nutritional requirements for humans mainly depend on plant-based food, such as that made from the edible portion of staple crops [1]. Wheat is one of the most important staple crops and makes a significant contribution to global food security. The global production volume of wheat in the 2019/2020 season amounted to more than 765 million tons, and approximately two thirds of this volume was consumed by humans [2]. 800 million people globally are still chronically undernourished, in countries with a relatively high consumption of wheat derivatives; these people have weaker immune systems and may be at a greater risk of certain severe illnesses caused by viruses [6,7]. The interest in nutritious and functional foods made from wheat has increased among consumers [8]. Increasing the nutritional content of staple crops continues to be a huge task for worldwide scientists. To meet the challenge of the nutritional crisis, nutritious properties of a raw food material should be used to develop food products with improved quality and health-related beneficial properties

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