Sprouting Time Affects Sorghum (Sorghum bicolor [L.] Moench) Functionality and Bread-Baking Performance.

Gaetano Cardone,Alessandra Marti,Rubina Rumler,Sofia Speranza,Regine Schönlechner

doi:10.3390/foods10102285

Abstract

Despite being considered a climate-resilient crop, sorghum is still underutilized in food processing because of the limited starch and protein functionality. For this reason, the objective of this study was to investigate the effect of sprouting time on sorghum functional properties and the possibility to exploit sprouted sorghum in bread making. In this context, red sorghum was sprouted for 24, 36, 48, 72, and 96 h at 27 °C. Sprouting time did not strongly affect the sorghum composition in terms of total starch, fiber, and protein contents. On the other hand, the developed proteolytic activity had a positive effect on oil-absorption capacity, pasting, and gelation properties. Conversely, the increased α-amylase activity in sprouted samples (≥36 h) altered starch functionality. As regards sorghum-enriched bread, the blends containing 48 h-sprouted sorghum showed high specific volume and low crumb firmness. In addition, enrichment in sprouted sorghum increased both the in vitro protein digestibility and the slowly digestible starch fraction of bread. Overall, this study showed that 48 h-sprouted sorghum enhanced the bread-making performance of wheat-based products.

Highlights

Sorghum (Sorghum bicolor [L.] Moench) is a staple food for the populations of the sub-Saharan regions, it is becoming an interesting ingredient in those formulations which are typical of the Western countries [1,2,3,4,5,6]
Sorghum is characterized by low protein digestibility, due to the presence of protein bodies formed by kafirins stabilized by disulphide bonds [9]
Sorghum should be treated in a way that improves its functionality, to obtain baked goods with satisfactory attributes for consumers

Summary

Introduction

Sorghum (Sorghum bicolor [L.] Moench) is a staple food for the populations of the sub-Saharan regions, it is becoming an interesting ingredient in those formulations which are typical of the Western countries [1,2,3,4,5,6]. These structures form a tight starch–protein matrix that leads to a decrease in starch and protein digestibility [9,10], and to a decrease in starch gelatinization properties [11,12] This is critical from a technological standpoint because starch pasting and gelation properties represent a key aspect in food products by affecting their final characteristics such as viscosity, structure, and texture. As regards wheat-based bread, the presence of sorghum (from 10%) decreases bread volume and increases dry mouthfeel and crumb firmness [13] For this reason, sorghum should be treated in a way that improves its functionality, to obtain baked goods with satisfactory attributes for consumers (i.e., high volume and crumb firmness). Several researchers have already investigated the effects of sprouting on chemical composition and functional properties of sorghum [4,14,16,17,18,19,20,21], to the best of our knowledge, the relation between these changes and the properties of sprouted sorghum-enriched bread have not been studied yet

Objectives

Methods

Results