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Tianrui Dong Final Thesis.pdf (5.99 MB)

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Spray Drying of Kefir with Encapsulating Agents to Mitigate Undesirable Volatile Flavor Compounds

Dong, Tianrui
http://rave.ohiolink.edu/etdc/view?acc_num=osu1595549687019366

Abstract Details

2020, Master of Science, Ohio State University, Food Science and Technology.
Kefir is a fermented dairy beverage that has been shown to successfully treat recurrent Clostridioides difficile infection (CDI) when consumed in conjunction with antibiotic treatment. Unfortunately, kefir has limited patient acceptance due to its strong acidic and fermented flavors produced during fermentation. To improve the flavor of kefir, further processing could be utilized, such as high heat spray drying, which can reduce undesirable volatile organic compounds (VOCs). To protect live microorganisms from high heat, encapsulating agents may be added to the mixture. In this study, the effect of spray drying with and without an encapsulating agent on commercial kefir’s water activity, moisture content, VOCs concentration, microbial viability and activity, microstructure, and sensory quality was analyzed. Kefir was spray dried in the pilot plant either without an encapsulating agent, with whey permeate, or with whey protein isolate. Water activity and moisture content of powder samples were obtained; volatile compounds concentration was measured using selected-ion flow-tube mass spectrometry (SIFT-MS); microbial viability was assessed by enumeration on selective media for Lactobacillus species and Lactococcus species, and bacteria were identified by 16S ribosomal DNA (rDNA) sequencing; microbial activity was assessed by inoculating kefir into milk and measuring change in pH over time; microstructure was examined using scanning electron microscopy (SEM) images, and sensory quality was determined by untrained panelists ranking samples and answering acceptability/likeability questions on kefir attributes. All three spray-dried kefir powder samples had water activity below 0.25 and water content below 5%, indicating high storage stability products. The total concentration for 29 VOCs in all spray-dried products was reduced significantly, with spray-dried kefir without encapsulating agent having the highest reduction of 61.2%, followed by kefir with whey permeate at 46.3%, and kefir with whey protein isolate at 36.7% reduction comparing to kefir control. Despite reduction in volatile compound concentration, spray-drying with and without encapsulating agent did not significantly improve the sensory likeability of kefir. Spray-drying also caused decreases in viable lactic acid bacteria (LAB) for all three samples; however, these samples still maintained probiotic status with LAB concentration above 106 CFU/ml. Acidification rates were slightly reduced for kefir containing encapsulating agents, and examination of microstructure shows encapsulation occurring in all three spray-dried products.
Valente Alvarez (Advisor)
Rafael Jimenez-Flores (Committee Member)
Ahmed Yousef (Committee Member)
141 p.
Food Science
encapsulation; spray drying; Clostridioides difficile; whey; lactic acid bacteria; kefir

Recommended Citations

Citations

  • Dong, T. (2020). Spray Drying of Kefir with Encapsulating Agents to Mitigate Undesirable Volatile Flavor Compounds [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595549687019366

    APA Style (7th edition)

  • Dong, Tianrui. Spray Drying of Kefir with Encapsulating Agents to Mitigate Undesirable Volatile Flavor Compounds. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1595549687019366.

    MLA Style (8th edition)

  • Dong, Tianrui. "Spray Drying of Kefir with Encapsulating Agents to Mitigate Undesirable Volatile Flavor Compounds." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595549687019366

    Chicago Manual of Style (17th edition)

osu1595549687019366
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