http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/162 Food Science and Technology 2026-04-19T15:36:30Z http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/1322 Quality improvement of ‘Phulae’ pineapple puree by high pressure processing Annisa Defriana Phunsiri Suthiluk ‘Phulae’ pineapple (Ananas comosus L. Merr) is a popular commodity and a Geographical Indication of Chiang Rai province, Thailand which is cultivated all year and typically consumed fresh. The oversupply and mismanaged postharvest of the crops leading to the lower price of the product. The aim of the study was to study the effect of high-pressure processing (HPP) on the quality improvement of ‘Phulae’ pineapple puree to be a value added for the product. The study was divided to 4 parts. Part I: preliminary study to select the suitable condition for the HPP, Part II: to study the effect of HPP during storage, Part III: to study the effect of HPP on Glycemic Index (GI) and dietary fiber, and Part IV: to study the effect of HPP on the anti-inflammatory activity. For the preliminary, ‘Phulae’ pineapple puree was prepared fresh and treated with HPP (400 and 600 MPa for 5, 10, and 15 mins) as well as heat treatment (HT) (80°C for 10 mins). The preliminary study shows that HPP could retain all of the quality attributes of ‘Phulae’ pineapple puree, producing higher antioxidant activity and bioactive compound in the product, with the same amount of microbial reduction as heat treated sample. HPP at 400 and 600 MPa for 10 mins were used for the further experiment alongside the fresh and HT sample, due to its high amount of antioxidant capacity and bioactive compound. During storage, the physiochemical attributes such as pH, TSS, and TA were stable but the color are slightly change. Despite the similar microbial safety during the storage with the HT sample, all the bioactive compounds and antioxidant activity of the samples were decreasing overtime during the storage. The study also found that GI of all samples is between 40.36 to 44.47, with HPP product showed the higher GI, due to the change of the sucrose to glucose during the treatment. However, the number for all samples are <55 which still considered as low GI food. The study also found out that HPP product have higher anti-inflammatory effect compared to fresh product. However, the amount reduced during storage. HPP treated sample at 400 MPa for 10 mins is the most optimal treatment for ‘Phulae’ pineapple puree due to its lower energy consumption (lower pressure) but similar result with the HPP treatment at 600 MPa for 10 mins. Thesis (M.Sc.) -- Food Science and Technology, School of Agro-Industry. Mae Fah Luang University, 2025 2025-01-01T00:00:00Z http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/792 Coffee characteristics evaluation from cherries to roasted Beans: A case of Northern Thai arabica coffee Sai Aung Moon Rattapon Saengrayap Thai coffee is celebrated globally for its distinct flavors and aromas, yet farmers encounter numerous obstacles, including unstable prices, limited market access, high production costs, and issues in farm and postharvest management. Key challenges include climate change, mix varieties growing, contamination from fungi and mycotoxins, insufficient facilities for drying, storage, and packaging, and variable weather impacting drying processes, which leading to inconsistent quality. Postharvest drying is critical for reducing microbial growth and developing desired flavors, while storage conditions significantly affect green coffee bean (GCB) quality. Extended storage, typically six months to a year, often leads to oxidation, resulting in quality loss through browning, aroma degradation, off-flavors, and increased spoilage risk. This research studies the impact of various drying, processing, and storage techniques on Thai coffee quality. In dying techniques on their physicochemical characterizes, this research examines the effects of different drying methods and post-harvest processing techniques on the quality of Thai GCB and roasted coffee beans (RCB). Thai coffee producers utilize sun drying (SD), controlled-environment drying (CED) at 20–30 °C and 50–55% RH, and fast drying (FD) at 30–45 °C to enhance quality and cupping scores. Results show that drying and processing methods significantly impact the physicochemical properties of GCB, including true density, moisture content, water activity, color, caffeine, trigonelline, chlorogenic acid, caffeic acid, sucrose, and fructose. CED produced the highest levels of these qualities, followed by SD and FD. The study also highlights that roasting decreases initial GCB qualities while developing characteristic flavors and aromas. Among post-harvest processes, dry processing (DP) yielded the highest caffeine, trigonelline, and chlorogenic acid levels, while honey processing (HP) increased sucrose and fructose, enhancing flavor complexity in the cup. In accelerated storage and packaging, this study investigated lipid oxidation in GCB under accelerated storage conditions (30, 40, and 50°C with 50% RH) and various packaging types: plastic woven (PW), low-density polyethylene (LDPE), and hermetic (GrainPro®/GP) bags. Samples collected every five days over 20 days were analyzed for oxidation markers, including acid value (AV), free fatty acids (FFA), peroxide value (PV), ρ-anisidine value (PAV), total oxidation value (TOTOX), and thiobarbituric acid reactive substances (TBARS), as well as moisture content, water activity, and color. Results showed primary and secondary oxidation with increasing AV, FFA, PAV, PV, and TBARS, impacting flavor and aroma. Higher temperatures accelerated lipid oxidation and quality degradation, with GP bags best preserving GCB quality by minimizing oxidation rates. The study highlights that selecting appropriate storage conditions and packaging materials, particularly hermetic packaging, is essential to maintaining GCB quality during storage. In accelerated storage and non-destructive techniques, this study evaluated the shelf-life and lipid oxidation of DP and HP coffees stored in GP bags under accelerated storage at 30, 40, and 50 °C with 50% RH. Using a kinetic model, the shelf-life was estimated at 45.67, 29.9, and 24.92 days for DP, and 60.34, 38.07, and 19.22 days for HP at 30 °C, 40 °C, and 50 °C, respectively. Partial least squares (PLS) modeling demonstrated predictive accuracy for TBARS (R² = 0.801) and peroxide values (PV) (R² = 0.469) with significant wavenumber ranges identified via ATR-FTIR spectroscopy as indicators of lipid oxidation. ATR-FTIR proved effective for non-destructive, rapid analysis of oxidation, and demonstrated that lower storage temperatures extended GCB shelf-life. Findings confirm that temperature and processing method significantly influence GCB shelf-life, with ATR-FTIR as a valuable tool for quality monitoring during storage. In roasting profiles, this study examines the effects of roasting levels and storage conditions on coffee quality by evaluating moisture content, color, peroxide value, shelf-life, and volatile compounds using SPME-GCMS. Coffee samples from Doi Chang, Thailand, processed by DP, WP, and HP were roasted to light (205°C), light-medium (210°C), and medium (218°C) levels, then stored in hermetic bags under accelerated conditions (30, 40, and 50°C, 50% RH) for up to 21 days. Roasting level and storage temperature significantly influenced (p<0.05) coffee quality, with higher temperatures accelerating degradation. Eighty-two volatile compounds were identified, with furans (35.20–53.55% d.w.), pyrazines (13.16–32.31% d.w.), and esters (4.21–16.70% d.w.) being the dominant contributors to aroma. Shelf-life at 30°C was longest for light roast (10.03–11.68 days), followed by light-medium (7.28–8.82 days) and medium (6.33–7.68 days). Washed coffee exhibited better long-term stability than honey and natural-processed coffee. While volatile compound concentrations generally declined during storage, organic acids, phenolics, and pyrazines increased due to thermal oxidation, with the most significant changes occurring at 50°C. These findings provide valuable insights for coffee roasters and buyers in optimizing storage conditions to preserve coffee quality and extend shelf-life. In dying techniques on their volatile compound and cupping, this study explores the effects of drying techniques; CED, SD, and FD combined with processing methods; DP, WP, and HP on the quality of roasted Thai coffee. CED-DP and CED-HP achieved the highest cupping scores of 83.17 ± 1.26 and 83.33 ± 0.58 points, respectively, with CED enhancing ester and nitrogenous compounds, SD increasing acids, alcohols, and ketones, and FD promoting acetate compounds. PCA revealed an 87.97% correlation between volatile compounds and cupping scores. DP was linked to high acidity, sweetness, and ester content; WP to uniformity and clean cup; and HP to sensory qualities like body and balance. CED proved most effective for enhancing acidity and flavor complexity, while FD showed higher pH and lower acidity, with each method contributing unique volatile profiles. Key volatile compounds were identified for each process, supporting the potential for tailored drying and processing methods to improve flavor and aroma in specialty coffee. This study offers insights for Thai producers and positions establishment for further research on optimizing coffee quality across different climatic conditions. Therefore, this research outlines a comprehensive strategy for improving specialty coffee quality through advancements in drying, storage, packaging, roasting, and analysis. Controlled environment drying (CED) dramatically enhanced physicochemical and sensory properties, particularly in dry and honey-processed beans. Accelerated shelf-life testing, along with enhanced lipid oxidation markers and ATR-FTIR spectroscopy, revealed new, non-destructive insights into coffee stability. Optimizing the roasting profile had a further impact on volatile component retention and shelf life. Concurrently, these advances contribute to a comprehensive approach for increasing flavor, uniformity, and storage stability, benefiting farmers, roasters, and quality systems in Thailand and abroad. Dissertation (Ph.D.) -- Food Science and Technology, School of Agro-Industry. Mae Fah Luang University, 2024 2024-01-01T00:00:00Z http://mfuir.mfu.ac.th:80/xmlui/handle/123456789/190 Effects of ultrasound-assisted extraction and tannase treatment on physicochemical, functional properties, and stability of green tea (Camellia sinensis var assamica) extract Haoyuan, Su This thesis explores the enhancement of catechin extraction from Green Tea (Camellia sinensis var. assamica) efficiency, extract quality and catechin stability, through various methodologies, including solvent extraction, ultrasound-assisted extraction (UAE), and tannase treatment, as well as the impact of storage conditions on catechin properties. In the first, the study compared solvent extraction and UAE methods for their effects on the physicochemical properties of catechins extract. UAE demonstrated superior efficiency in catechin extraction, achieving higher yields and improved higher total polyphenol content (TPC) and antioxidant capacity of catechin extract compared to conventional solvent extraction. UAE on condition tea : 50% ethanol v/v (1：20) at 20min showed the highest extract yield 22.99 ± 0.08%, catechin content 33.75 ± 0.15 (g/100 g db), TPC 64.02 ± 0.16 (g/100 g db) and antioxidant capacity. The second investigated the effects of tannase in modifying the physicochemical and functional properties of catechin extract. Tannase treatment significantly impacted the TPC and antioxidant capacity of catechins. Although tannase treatment reduced content of catechins, and it provided greater stability during storage by minimizing degradation. This stabilization effect was more pronounced at lower temperatures. In the final, the stability of catechins was assessed under different storage conditions, specifically at freezer (-20°C) and incubator (30°C). Untreated catechin samples showed considerable degradation in TPC, antioxidant activity, and individual catechin content over an 8-week period, with more severe declines at incubator. Tannase-treated samples, however, exhibited better stability, with slower declines in catechin content and antioxidant activity. Overall, the results demonstrated that ultrasound-assisted extraction (UAE) is a highly effective technique for obtaining catechin-rich extracts with superior antioxidant properties compared to traditional solvent extraction methods. Furthermore, tannase treatment proved to be a promising strategy for improving the long-term stability of catechins, despite its initial reduction in catechin content. This stability enhancement is especially critical for applications where maintaining antioxidant activity over extended storage periods is essential. The research also highlighted the significant impact of storage conditions on catechin degradation. Lower temperatures, such as those in freezer storage (-20°C), were shown to significantly mitigate the loss of catechin content, total polyphenols, and antioxidant capacity compared to higher storage temperatures (30°C). These findings provide valuable insights for the development and preservation of catechin-rich products, emphasizing the importance of employing advanced extraction techniques and stabilizing agents to maintain the quality and efficacy of catechins. Master of Science. Food Science and Technology. Mae Fah Luang University 2024-01-01T00:00:00Z