Document Type

Dissertation - Open Access

Award Date

2018

Degree Name

Doctor of Philosophy (PhD)

Department

Dairy Science

First Advisor

Padmanaban Krishnan

Abstract

The first objective of this research was to enhance nutritional, rheological, sensory profiles, and shelf life of wheat-based pita bread using chickpea (CP) and food grade distiller’s dried grains (FDDG) as fortification ingredients. CP and FDDG are both high-protein and high-fiber ingredients. Nutritional efficacy was evaluated. Dough rheology and product texture were also analyzed. Chemical, physical, and rheological properties of blends, doughs and finished products were evaluated and the results showed an increase in protein, fat, ash, and total dietary fiber with an increase of FDDG and CP in the wheat-based food formulation. Moisture content was decreased in both flour blends and pita breads with the increase of FDDG and CP substitution levels. Amino acids scores were improved by different fortification levels of either chickpea or FDDG or combinations of the two ingredients in comparison of all treatments to the all-wheat control pita bread. Fortification with 10% FDDG improved amino acid scores by 15%, whereas fortification with 20% FDDG improved AA score by 22% (over control wheat flour pita). Also, fortification with 10% chickpea improved amino acid scores by 20%, whereas fortification with 20% chickpea improved amino acid scores by 28%. Color results indicated decreased L* values (brightness), and a*(redness), but increased b*(yellowness) levels with increased FDDG levels. With increased chickpea levels in pita formulation, L* and b* values decreased, and a* increased. Rheological evaluation from Mixolab and Farinograph analysis showed that fortification in general, yielded pronounced effects on dough properties. Both FDDG and CP showed increased water absorption, higher dough development time, and lower dough stability time when compared to the wheat-only control. Texture analyzer results showed that the force required to break the dough increased, whereas the dough extensibility declined as the fortification level of either or chickpea and FDDG increased. Texture Analyzer results also showed that fortified pita required a greater force for tearability as determined by the burst rig and the tug fixture tests. Burst distance and tug distance were also reduced with increased fortification level of both chickpea and FDDG. Shelf life evaluation showed that wheat pita bread substituted with 10% chickpea pita bread had the same shelf life time as control pita bread, whereas fortifying with 20CP% increased the shelf life by 6 hours. Also, 10% FDDG fortification increased shelf life by 6 hours whereas fortifying with 20% FDDG increased the shelf life by 12 hours, in contrast to the control pita bread. Fortifying with 20CP-10D% increased the shelf life of the pita bread by 24 hours. The longest shelf life was found in 20 % FDDG-10% chickpea treatment which was 30 hours longer than the control all-wheat pita bread. Sensory analysis was done for all pita breads and showed that all products tested were deemed to be acceptable relative to the control all-wheat flour pita bread. Our findings show that pita breads containing up to by 30% chickpea and FDDG were determined to be acceptable to the sensory panelists. The second objective of the study was to test the efficacy of high levels of dietary fiber, protein, fat, and antioxidants (phenolic compounds and carotenoids) by employing ingredients such as chickpeas and food grade distiller’s grains in the development of low glycemic response foods. Pita bread containing 10% CP yielded an IAUC of 85.46 mmol.min/L while the 20% CP showed IAUC of 56.32mmol.min/L. FDDG pita breads with 10% FDDG showed IAUC of 81.21 mmol.min/L while the 20% FDDG pita bread resulted in an IAUC of 46.23 mmol.min/L. Moreover, IAUC for the 70W-20CP-10D pita was 40.06 mmol.min/L, and 36.53 mmol.min/L for 70W-20D-10CP pita. Inclusion of CP and FDDG in wheat flour, separately and in combinations (70:20:10 & 70:10:20), brought about improvements in the GR when compared to control wheat pita. The third objective of this study was to develop formulations for a nutrient-dense energy bar containing wheat flour, chickpea flour, and FDDG and to determine proximate composition and sensory characteristics. It is hypothesized that cereal based foods can be effectively fortified with chickpea and FDDG to produce products of higher nutrient content that can be used in emergency food programs. Results showed sign ificantly? higher values for protein, fiber, carbohydrates, and fats content in HEB containing CP and FDDG in contrast to unfortified all wheat HEB. Sensory scores of fortified HEB were acceptable as judged by panelists. HEB, particularly those containing 25% FDDG, 25% CP, and 50% CP, were highly enriched with nutrients and exceeded nutritient content in HEB currently employed by food aid programs. HEB containing 50% FDDG had particularly high protein content (16.6g/100g). Overall sensory results showed that 50% CP fortified HEB received a moderate score (3.86), whereas 25% FDDG, 25% CP, and 50% FDDG HEBs received scores of 4.0, 4.18, and 4.12, respectively. These results show good potential for the use of CP & FDDG in High Energy Bars for emergency food programs.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

333

Publisher

South Dakota State University

Rights

In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/

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