Almonds are the number one tree nut produced in the U.S. and the number one consumed tree nut worldwide. Despite their economic, nutritional, and consumer value, almonds are among the top foods responsible for eliciting allergies in sensitive individuals. Amandin is the major storage protein and allergen in almond, accounting for roughly 70% of the total soluble protein content. Almonds are frequently subjected to heat processing prior to consumption which may potentially alter the structure and allergenic properties of amandin. The objective of this study was to determine how heat treatment influences the structure and immunoreactivity of amandin in thermally processed almond seeds. Whole Nonpareil almond seeds were subjected to autoclaving (121°C, 15 psi, for 15 and 30 min), blanching (94°C for 5 and 10 min), frying (191°C for 1 min), microwaving (1000 W for 1 min and 500 W for 3 min), and roasting (140 and 160°C for 30 min each; and 168 and 177°C for 12 min each). Processed seeds were ground and amandin was isolated from defatted almond flour using cryoprecipitation at 4°C. Soluble protein content was determined by the Bradford and Lowry methods. Immunoreactivity was assessed using enzyme-linked immunosorbent assay (ELISA), Western blot, and dot blot using two different murine monoclonal anti-amandin detection antibodies, 4C10 and 4F10. Structural changes were assessed using ultraviolet (UV) absorption and fluorescence spectroscopy. Results are reported as mean ± SEM and one-way ANOVA was performed to compare means for difference. Post hoc analysis was performed using Fisher’s least significant difference at p ≤ 0.05. ELISA immunoreactivity was assessed by the ratio (R) = signal at 50% maximum signal of processed sample/signal at 50% maximum signal of unprocessed control. The range of R values for the tested processed samples were 0.36 ± 0.02 to 1.54 ± 0.10* for 4C10 (LSD=0.26) and 0.37 ± 0.05* to 1.23 ± 0.17* for 4F10 (LSD=0.21). Western blots and dot blots were consistent with ELISA results. Second-derivative UV spectroscopy was used to quantify tertiary stuctural changes through the determination of derivative peak ratios between two successive peaks. The ratios ranged from 2.31 ± 0.44 to 5.67 ± 0.54. Relative fluorescence intensities (F/F0) ranged from 1.02 to 1.22. The immunoreactivity of amandin in processed almond seeds as assessed by ELISA, Western blot, and dot blot varied depending on the type of processing treatment undergone. While immunoreactivity decreased under certain conditions, it was never eliminated, indicating antigenic stability of amandin towards thermal processing. Under certain processing conditions, changes in second-derivative UV spectra and fluorescence intensity were observed suggesting the occurrence of heat-induced structural changes. / A Thesis submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2016. / June 16, 2016. / Almond, Amandin, Immunoreactivity, Protein structure, Thermal processing, Tree nut allergy / Includes bibliographical references. / Shridhar K. Sathe, Professor Directing Thesis; John G. Dorsey, Committee Member; Qinchun Rao, Committee Member; Michael Roper, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_366461 |
| Contributors | Zaffran, Valerie D. (authoraut), Sathe, Shridhar K. (professor directing thesis), Dorsey, John G. (committee member), Rao, Qinchun, 1974- (committee member), Roper, Michael Gabriel (committee member), Florida State University (degree granting institution), College of Human Sciences (degree granting college), Department of Nutrition, Food, and Exercise Science (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (63 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
Page generated in 0.0013 seconds