Selected Anti-nutritional Factors and &amp;lt;i&amp;gt;In-vitro&amp;lt;/i&amp;gt; Protein Digestibility of Some Sorghum Types as Influenced by Germination Time During Malting

Mohammed Atanda Usman

doi:10.11648/j.ijfsb.20180302.11

Abstract

The effect of germination time, during malting, on phytate and tannin concentration as well as on the <i>In-vitro</i> protein digestibility of some sorghum types was investigated. The increase in the germination time led to a decrease in the phytate content from the initial range of 1004.6-1097.4 mg/100g, at zero-hour germination, to a range of 457.2-626.3 mg/100g at 48-hour germination time. A further decrease in the phytate content was obtained at 96-hour germination time with a range of 215.4 -298.3 mg/100g. A maximum of 71.5-79.2% phytate reduction capacity at 96-hour germination time was attainable with the sorghum types. The increase in germination time also caused the tannin concentration to decrease. The initial tannin concentration (0.23-4.47 mg/g), at zero-hour germination time, decreased to 0.15-3.35 mg/g at 48-hour germination time while a range of 0.13-3.07 mg/g was obtained at 96-hour germination time. A maximum of 25.9-45.8% tannin reduction capacity at 96-hour germination time was attainable with the sorghum types. The <i>In-vitro</i> protein digestibility of the sorghum types increased from the initial level (32.1-45.1%), at zero-hour germination time, to 42.8-61.3% at 48-hour germination time while that of 96-hour germination time was 46.7-64.8%. It may be concluded that the decrease in the anti-nutritional factors and improvement in the protein digestibility of sorghum types during the malting process was essentially a function of germination time and sorghum grain variability.

Highlights

Sorghum (Sorghum bicolor (L) Moench) is an important cereal grain in the tropical arid and semi-arid zones of the world, and has been noted to be the fifth ranked cereal after wheat, maize, rice and barley in importance [1]
Three classes of sorghum grains were used for this study and these include (1) Local sorghum type (Pelipeli and Kwaya) obtained from Adamawa Agricultural Development Agency, Yola, Nigeria; (2) Improved sorghum type (SAMSORG-14 and SAMSORG-17) obtained from the Institute of Agricultural Research (IAR), Samaru, Nigeria; and (3) Hybrid sorghum type (Hybrid A and B) sourced from Lake Gerio Research Farm of the River Basin Development Authority (RBDA), Yola, Nigeria
Experimental samples (300 g) of each sorghum grain type and barley were taken and the malting process follows the procedure of Palmer [21]

Summary

Introduction

Sorghum (Sorghum bicolor (L) Moench) is an important cereal grain in the tropical arid and semi-arid zones of the world, and has been noted to be the fifth ranked cereal after wheat, maize, rice and barley in importance [1]. The consumption of sorghum serves as a major source of proteins and calories in the diets of people in Africa [2], thereby meeting their food security requirements. The utilization of sorghum grains includes human food uses, serving as one of the most important weaning food cereals in low-income and high-income countries [3]. Other areas of sorghum usage, in Africa, include the production of many traditional food products such as ogi, eko, kunnu and tuwo [4], fermented beverages such as mahewu [5], couscous and dolo [6], injera, kisra and ugali [7], among others. The negative consequence of tannin in sorghum-based diet has to do with its interference with protein digestion by binding dietary protein into an indigestible form [10]

Methods

Results

Conclusion