Physicochemical evaluation and Fourier transform infrared spectroscopy characterization of quality protein maize starch subjected to different modifications.

Olugbenga Olufemi Awolu,Joshua Wisdom Odoro,Jumoke Bukola Adeloye,Oluranti Mopelola Lawal

doi:10.1111/1750-3841.15391

Olugbenga Olufemi Awolu, Joshua Wisdom Odoro + Show 2 more

Open Access

https://doi.org/10.1111/1750-3841.15391

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Abstract

Quality protein maize (QPM) is a biofortified maize rich in lysine and tryptophan, essential amino acids required in human nutrition. This research therefore characterizes native and modified starches from QPM by evaluating the physicochemical properties, Fourier transform infrared spectra (FTIR), and pasting properties. The native QPM starch was modified by oxidation, acetylation, pregelatinization, and acid thinning techniques. The starch yield of native QPM was 43.80%, while that of modified starches were from 88.22 to 98.34%. The moisture content of the native and modified starches was from 4.56 to 9.20 g/100g. Modifications significantly (P ≤ 0.05) reduced the lipid, protein, and amylose contents of the QPM. While the native starch had 0.72 g/cm3 bulk density, modified starches were between 0.59 and 0.88 g/cm3; chemical modification reduced the bulk density and physical modification increased it. In addition, all the modifications except oxidation significantly (P ≤ 0.05) increased water absorption capacity. The oil absorption of the starch samples was increased by modification techniques used with the exception of physical modification. Chemical modification reduced the viscosity of QPM starch while physical modification increased it. The reducing sugar content of the starch was reduced by both the physical and chemical starch modification techniques. Acetylated sample exhibited the highest swelling power while acid‐thinned sample had the least. The major functional groups identified via FTIR were OH, C‐H, C=H, and C≡H. Modifications did not affect the functional groups as all the native and modified starches (except oxidized sample) all have similar spectrum and bands stretch.Practical ApplicationThe study contributes to existing knowledge on valorization of modified starch from quality protein maize. Profiling the chemical attributes of modified starches is especially valuable in novel food processing techniques.

Highlights

Quality protein maize (QPM) is a biofortified maize rich in lysine and tryptophan, essential amino acids required in human nutrition
Α-d-(1,4) glycosidic linkages, while the amylopectin fraction of Humans and animals derive their energy from starch and it is a the starch is of a highly branched polymer which has one of the predominant food reserve substance found in green plants
Physical modwhich is either linear or slightly branched.Amylose is a linear poly- ification is achieved by using moisture and heat to treat the starch while chemical methods involve esterification, etherification, and crosslinking or decomposing the starch

Summary

Introduction

Quality protein maize (QPM) is a biofortified maize rich in lysine and tryptophan, essential amino acids required in human nutrition. While the native starch had 0.72 g/cm bulk density, modified starches were between 0.59 and 0.88 g/cm; chemical modification reduced the bulk density and physical modification increased it. Α-d-(1,4) glycosidic linkages, while the amylopectin fraction of Humans and animals derive their energy from starch and it is a the starch is of a highly branched polymer which has one of the predominant food reserve substance found in green plants It highest molecular weights recognized among naturally occurring serves as an energy reservoir which is readily converted into use- polymers (Karim, Norziah, & Seow, 2000). The matured maize kernel comprises about 70% starch of the from quality protein maize (QPM) might possess an increased dry weight making the maize starch of major economically impor- amylopectin content, higher swelling capacity, and a lower risk of tant component of the crop (Ji et al, 2003). Physical modwhich is either linear or slightly branched.Amylose is a linear poly- ification is achieved by using moisture and heat (pregelatinizamer and has its makeup from glucopyranose units linked through tion) to treat the starch while chemical methods involve esterification, etherification, and crosslinking or decomposing the starch

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