@phdthesis{Le2025, author = {Le, Ngoc Duc}, title = {Investigation of the potential allergenicity and coloration of peanut and hazelnut regarding different high-temperature processing methods}, volume = {2025}, edition = {1. Auflage}, publisher = {Hochschule Geisenheim}, address = {Geisenheim}, url = {http://nbn-resolving.de/urn:nbn:de:hebis:2083-1055}, school = {Hochschule Geisenheim University}, pages = {i -- 259}, year = {2025}, abstract = {Peanut and hazelnut are important sources of protein and are often processed using methods like roasting, baking, frying, and cooking. However, since both are major allergens, it is crucial to study how processing affects their potential to cause allergic reactions. This doctoral research is part of the ErdHase project, which aims to understand the impact of high-temperature processing on the biochemical and physical properties these nuts. The first goal of the study was to determine suitable parameters to define the processing degree of peanuts and hazelnuts, such as L* (lightness) and the browning index (BI). Their reference values, which depend on raw materials and market preferences, were derived based on commercial products and experimental roast models. The study employed various processing methods including drum roasting, infrared roasting, deep frying (for peanut), and fluid-bed roasting (for hazelnut). To study the effects of temperature and time on coloration and moisture, response surface methodology (RSM) was used. This approach was considered effective in reducing the number of experiments needed while maintaining reliable results. As temperature and time increased, the moisture content decreased, and the browning increased, which was consistent with prior research. Additionally, the study found that the ∆E2000 total color difference was more accurate than ∆E76 for assessing the total color difference between processed samples and commercial products. Combining all the collected data, it could be seen that for both Virginia and Runner peanuts and hazelnut, infrared roasting reduced the MC faster and drum roasting affected the color more drastically at the same temperature compared to other approaches. Deep frying of peanut and fluid bed roasting of hazelnut requires higher temperature profiles to achieve a comparable effect. The second part of the research focused on optimizing protein extraction from both raw and processed peanuts and hazelnuts. An extraction protocol using Tris-containing buffer with mild heating was developed and optimized using RSM, yielding good results with minimal denaturation of proteins. The study also showed the protein composition of processed peanuts and hazelnuts using SDS-PAGE and NativePAGE. Processing methods like roasting and frying reduced the protein yield, and allergen bands were detected, although patient-specific IgE binding varied. Further research involved the development of buckwheat-based foods (cream alternative and cookies) to test for the allergenicity in ELISA. Infrared and drum roasting was found to have the greatest impact on allergen recovery. Additionally, a food-grade protease was applied for improving allergen extraction. This enzyme significantly increased allergen recovery without affecting ELISA performance, offering a potential solution to the problem of low extractability of processed allergens. In summary, the presented doctoral thesis, on the one hand, provided additional investigations regarding different high-temperature processing methods on coloration and moisture content of peanut and hazelnut. It confirmed previous observation, defined a new approach of combining L* and BI to evaluate processed products. On the other hand, on the biochemical aspect of processed peanuts and hazelnuts, this work provided an optimized extraction protocol that potentially works for a wide spectrum of processed samples. In addition, incurred buckwheat-based products and enzyme-assisted extraction for ELISA showed promising results for future applications regarding their potential allergenicity.}, language = {en} }