Doctor of Philosophy (PhD)


School of Nutrition and Food Sciences

Document Type



One of the major concerns of the hot sauce manufacturers is separation of sediments and layering of the sauce. Separation is an undesirable production condition because consumers view this as a defect which consequently increases manufacturing costs. Pectins play an important role in pepper processing since it forms gels and influences the final viscosity of the sauce. Hence, its integrity during processing influences the quality of the final product. Failures in pectin stability can sometimes be related to the presence of enzymes. Understanding how the pectin enzymes function during fermentation of pepper sauce is a necessary step in controlling the enzymatic activity, and thereby reducing production cost and the risk of having a poor quality food product. Given the lack of information in the enzymatic activity of pectin enzymes during the processing of hot sauce, our objectives were to partially purify pectin methylesterase (PME) from hot peppers, evaluate the properties of the enzyme, and investigate lactic acid bacteria isolated from pepper mash during fermentation that could have the potential of producing and excreting pectinolytic enzymes. In this study, PME was separated by weak anion-exchange and affinity chromatography. Based on our SDS-PAGE results, two major bands were present at 22 kDa and 36 kDa. Our research revealed under acidic conditions, high salt concentrations, and temperatures above 50°C, PME can be effectively inactivated. We collected thirty mash samples (1-month aged and 36-months aged) under normal processing conditions from a local processing plant. All samples showed the presence of Lactobacillus as indicated by PCR. Quantitative real-time polymerase chain reaction (QRT-PCR) was employed to quantify total bacteria and lactobacilli in the samples. The percentage share of Lactobacillus in the counts was higher in 36-month aged samples than 1-month aged samples. Based on the concentrations, this bacteria plays a major role over the course of the fermentation aging process of pepper sauce.



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Committee Chair

Wilson, Paul W.



Included in

Life Sciences Commons