Soy Protein is an Efficacious Alternative to Whey Protein in Sorghum–Soy Fortified Blended Foods in Rats

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ABSTRACT

Background

Previously we found that extruded corn–soy blend (CSB) and sorghum–soy blend (SSB) fortified blended foods (FBFs) containing whey protein concentrate (WPC) were equally nutritious food aid products. WPC provides high-quality protein; however, it is the most expensive ingredient in these FBFs.

Objectives

The primary objective of this study was to determine if soy protein can serve as an alternative to WPC and the secondary objective was to evaluate different sucrose amounts in the FBFs.

Methods

Nine extruded FBFs were formulated: 1 CSB and 1 SSB, both containing 9.5% WPC and 15% sucrose, served as comparison FBFs. Three additional CSB and 4 SSB FBFs were formulated containing no WPC, but with increased soy flour to meet protein requirements and varying sucrose concentrations. The sucrose content ranged from 0% to 10% for the CSBs and 0% to 15% for the SSBs. Male weanling Sprague Dawley rats were individually housed and divided into 10 diet groups (n = 9–10) which consumed either AIN-93G or a dry FBF for 28 d. At study conclusion, blood, livers, and body composition data were collected. Results were analyzed using 1-factor ANOVA with Tukey’s test.

Results

Outcomes were not significantly different between the SSB groups, with the exception of significantly higher protein efficiency for the WPC-containing group. Among the CSB groups, caloric and protein efficiencies were significantly higher for the WPC-containing CSB group. There were no significant differences in hemoglobin or hepatic iron concentrations between FBF groups, but hepatic iron concentrations were significantly higher in all FBF groups than in the AIN-93G group. Groups consuming diets with ≤10% sucrose had significantly higher bone mineral density than groups consuming diets with 15% sucrose.

Conclusions

These results suggest that extruded SSB, but not necessarily CSB, FBFs with soy protein and 5%–10% added sucrose are efficacious and cost-effective alternatives to WPC-containing FBFs.

Keywords:

fortified blended foods
soy
sorghum
corn
sucrose
iron
rats
growth
protein quality
bone mineral density

Abbreviations used:

BMD
bone mineral density
CSB
corn–soy blend
CSB-15WPC
corn–soy blend with whey protein concentrate and 15% sucrose
CSB-0
corn–soy blend with 0% sucrose
CSB-5
corn–soy blend with 5% sucrose
CSB-10
corn–soy blend with 10% sucrose
FAQR
Food Aid Quality Report
FBF
fortified blended food
HFCS
high-fructose corn syrup
PER
protein efficiency ratio
SPI
soy protein isolate
SSB
sorghum–soy blend
SSB-15WPC
sorghum–soy blend with whey protein concentrate and 15% sucrose
SSB-0
sorghum–soy blend with 0% sucrose
SSB-5
sorghum–soy blend with 5% sucrose
SSB-10
sorghum–soy blend with 10% sucrose
SSB-15
sorghum–soy blend with 15% sucrose
WPC
whey protein concentrate.

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Supported by USDA Micronutrient Fortified Food Aid Pilot Project contract FFE-621-2012/033-00 (to SA); the Kansas Agricultural Experiment Station also provided funding for the animal study (to BLL). This sensory analysis research is based on work supported in part by the National Institute of Food and Agriculture, USDA, Hatch under accession number 1016242 (to EC).

Author disclosures: the authors report no conflicts of interest. BLL is an Academic Editor on Current Developments in Nutrition and played no role in the evaluation of the manuscript.

Supplemental Tables 1–6 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/cdn/.