Date of Award

Spring 1-31-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Food Science

First Advisor

Lilian Were, Ph.D.

Second Advisor

Fredric Caporaso, Ph.D.

Third Advisor

Anuradha Prakash, Ph.D.

Abstract

The two color-developing reactions that occur when soft pretzels are baked using sunflower flour (SFF) in aqueous alkali environment are chlorogenic acid (CGA)-quinone induced greening and Maillard browning. This study aimed to determine how CGA content in two different SFFs containing 45% and 55% protein (Heliaflor® 45 and 55, respectively) affected the formation of green trihydroxybenzacridine (TBA) and Maillard reaction products (MRPs) in soft baked pretzels. Pretzels were baked with five doughs prepared using a pre-blended gluten-free flour, consisting of sweet white rice flour, whole grain brown rice flour, potato starch, whole grain sweet white sorghum flour, tapioca flour, and xanthan gum: control (no SFF) and doughs replacing 3.65% and 7.30% GF flour with Heliaflor® (HF) 45 and 55. Pretzels were used for Hunter L, a, b color, and proximate analysis. Flour mixtures containing HF 45, HF 55, gluten free flour (GF) + HF 45, GF + HF 55 with 5% glucose, sucrose or sorbitol were also prepared. The supernatants from the centrifuged flour mixtures were used to quantify Schiff bases, CGA, melanoidins, and trihydroxybenzacridine (TBA) derivatives. The precipitates were dehydrated in a vacuum oven and FTIR analysis was used to identify changes that occurred in the secondary structures of proteins. Pretzels prepared with SFF contained CGA, whereas mixtures prepared with GF flour, without SFF, did not develop CGA and instead revealed the presence of non-CGA hydroxycinnamic acids (HCAs) such as caffeic, ferulic, and p-coumaric acid. The mixture containing HF 55 had the highest Schiff base, CGA, melanoidin, and green TBA content. There was no significant difference in CGA and MRPs between mixtures prepared using SFF containing 45% vs 55% protein or between the different sweeteners used. Greening in pretzels stored at ambient temperature increased 18 hours post-baking. The quantity of SFF used can be decreased to obtain the desirable shade of green color in the pretzels. The formation of MRPs such as excessive browning and Schiff bases can be decreased by decreasing the concentration of SFF to develop a gluten-free baked pretzel containing SFF for bakeries and restaurants.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Available for download on Sunday, January 31, 2021

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