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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Production and characterization of bioactive peptides from soy fermented foods and their hydrolysates

Gibbs, Bernard F. January 1999 (has links)
No description available.
12

Physico-chemical and molecular characterization of soy bread containing almond

Lodi, Alessia, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 160-175).
13

Production and characterization of bioactive peptides from soy fermented foods and their hydrolysates

Gibbs, Bernard F. January 1999 (has links)
Biologically active peptides are found in the amino acid sequence of bacterial, fungal, plant and animal proteins. They are among the most potent pharmacologically active agents. Examples are venom toxin (mellitin), hormones (oxytoxin), opioids (beta-endorphin) and enzyme inhibitors (hirudin). These bioactive peptides are released from proteins by enzymatic proteolysis by processes such as gastrointestinal digestion or food processing. / Soybeans were fermented with Bacillus subtilis ATCC 41332 and Rhizopus oligosporus NRRL 2710 to produce tempeh and natto, respectively. Samples were taken throughout the fermentation and analysed for biochemical changes. Protease activity and ammonia production detected in the early stage of the tempeh preparation suggested that protein was used as a carbon source during that period and contributed to a rise in pH. Bacillus subtilis did not produce ammonia and maintained a constant pH throughout the fermentation. The total peptides produced were at a maximum at the end of the fermentation cycles. Angiotensin-converting enzyme inhibitory activity increased throughout both fermentations. A method was developed to monitor the production of biogenic amines throughout the fermentation. The levels of biogenic amines increased dramatically as the fermentation proceeded until maturity was achieved. In the tempeh fermentation, the polyamines levels rose from the initial 19 ppm to final concentration of 862 ppm, with the largest increase in histamine (616 ppm) followed by putrescine (204 ppm). These compounds also contributed to the pH rise from 3.8 to 6.8 in 24 h. In the Bacillus fermentation, the total polyamines at the end of the fermentation was 110 ppm with the largest increase in putrescine, followed by cadaverine. / Soy hydrolysate and the soy fermented foods, natto and tempeh, were deglycosylated and treated with proteolytic enzymes (plasma proteases, kidney homogenate, pronase, pepsin, thermolysin, trypsin, chymotrypsin and proteinase K) to produce oligopeptides. Several peptides were isolated, purified and characterized. The peptides had a range of biological activities---angiotensin converting enzyme inhibitory, antithrombotic, surface tension, antibacterial, anti-oxidant and insulin-modulating activities. Three potent ACE inhibitors, three thrombin inhibitors, five peptides with surface-active properties and one peptide with antibacterial activity were identified. They were all derived from glycinin and were found in the plasma protease digest, the kidney homogenate digest and the pronase digest of fermented foods. Another sequence ELLVYLL possessed good surface active properties but its precursor could not be identified. However, it was analogous to a peptide produced by Bacillus subtilis , and was probably synthesized during fermentation. Peptide analogs were synthesized and evaluated. They showed similar activities. Other sequences of known inhibitors, TPKDFEEIPEE, FPRGGG and DFEEIPEEL, were found to be competitive substrates for ACE.
14

Properties of proteins and food products from micronized soybeans

Pg. Metussin, Dk. Rosidah January 1990 (has links)
The effect of infra-red heating (micronization) on the composition and textural properties of full-fat soybeans and its product (soy isolate, soymilk and tofu) were investigated. There was little difference in the overall proximate composition between the micronized and processed soybeans. Yield, protein content and textural properties of tofu made from micronized beans using standard procedures (70$ sp circ$C and CaSO$ sb4$.2H$ sb2$O as coagulating agent) were lower than those of tofu from unprocessed beans; tofu prepared from micronized beans and coagulated at 90$ sp circ$C using a mixture of citric acid (0.01M) and calcium sulphate (0.03M) showed improved characteristics. The microstructure of tofu prepared from micronized beans lacked the regularity of honeycomb-like structure as shown by tofu from unprocessed beans. / Functional, biochemical and nutritional properties of the micronized soybeans, soy isolate, soymilk and tofu were studied. The results indicate the following: the digestibility of micronized soybean (84.3%) was higher compared to the unprocessed soybean (76.5%); the available lysine content of soy isolate, soymilk and tofu from micronized soybeans were higher than the corresponding products derived from unprocessed beans; the unprocessed soybean flour displayed maximum foam capacity at pH 9.0 while the micronized soybean flour showed no foam capacity at pH 3.0 and 5.0; polyacrylamide-disc gel electrophoresis showed that heat treatment by micronization had little effect on the protein constitution of the soybean and on the protein-carbohydrate interaction but induced some interactions of protein and lipid components in the soybeans.
15

Levels of trypsin inhibitors in soy-based foods and modulation of their antinutritional effects by dietary amino acids

Peace, Robert William January 1991 (has links)
Levels of soybean trypsin inhibitors (SBTI) in soy-based infant formulas were measured and found to range from 3 to 28% of the activity measured in raw soybeans, with higher activity usually present in ready-to-feed compared to concentrate or powder formulations. Experiments were conducted to examine the influence of dietary SBTI on growth, serum enzyme, lipid and free amino acids and hepatic S-adenosylmethionine (SAM) status in weanling male rats. Diets containing graded amounts of SBTI were fed with and without the methionine antagonist ethionine. Changes in growth, serum enzymes, lipid and amino acid parameters in rats fed SBTI or ethionine indicated lipotrope deficit and compromise of the transsulfuration pathway. The combination of SBTI and ethionine exacerbated many of the symptoms and methyl donor deficit was indicated by hepatic SAM status. Methionine supplementation of SBTI + ethionine diets was beneficial at moderating changes while cysteine supplementation was not.
16

Development and evaluation of new wild blueberry and soy frozen dessert /

Teh, Yeah Hoong, January 2004 (has links) (PDF)
Thesis (M.S.) in Food Science and Human Nutrition--University of Maine, 2004. / Includes vita. Includes bibliographical references (leaves 86-96).
17

Development and Evaluation of New Wild Blueberry and Soy Frozen Dessert

Teh, Yeah Hoong January 2004 (has links) (PDF)
No description available.
18

Levels of trypsin inhibitors in soy-based foods and modulation of their antinutritional effects by dietary amino acids

Peace, Robert William January 1991 (has links)
No description available.
19

Effects of lipase supplementation and salt replacement on the chemical, microbiological and organoleptic qualities of white Chinese fermented beancurd.

January 2005 (has links)
Chang Pui Sze. / Thesis submitted in: October 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 204-227). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract (In English) --- p.ii / Abstract (In Chinese) --- p.iv / List of Tables --- p.vi / List of Figures --- p.x / Contents --- p.xii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Historical Background of Sufu --- p.1 / Chapter 1.2 --- Nutritional Benefits of Sufu --- p.2 / Chapter 1.3 --- Production Steps --- p.2 / Chapter 1.3.1 --- Preparation of Tofu --- p.5 / Chapter 1.3.2 --- Preparation of Pehtze --- p.5 / Chapter 1.3.3 --- Salting or Brining --- p.8 / Chapter 1.3.4 --- Aging --- p.9 / Chapter 1.4 --- Local Varieties of Sufu --- p.9 / Chapter 1.5 --- Other Types of Sufu Fermentation --- p.10 / Chapter 1.6 --- Biochemical Changes during Sufu Production --- p.11 / Chapter 1.6.1 --- Protein Faction --- p.12 / Chapter 1.6.2 --- Lipid Fraction --- p.14 / Chapter 1.6.3 --- Carbohydrate fraction --- p.14 / Chapter 1.7 --- Sufu Flavor --- p.14 / Chapter 1.7.1 --- "Water-soluble Peptides, Free Amino Acids and Tasty Oligopeptides" --- p.14 / Chapter 1.7.2 --- Nucleotide Contents in the Taste of Sufu --- p.15 / Chapter 1.7.3 --- Effects of Ethanol on Flavor Development --- p.15 / Chapter 1.7.4 --- Volatile Components in Sufu --- p.16 / Chapter 1.8 --- Microbiological Safety of Sufu --- p.18 / Chapter 1.9 --- Existing Problems in Sufu Production --- p.19 / Chapter 1.10 --- Acceleration of Sufu Maturation by Adding Exogenous Lipase --- p.20 / Chapter 1.10.1 --- Proteases --- p.22 / Chapter 1.10.2 --- Problems with Proteases --- p.24 / Chapter 1.10.3 --- Lipases --- p.25 / Chapter 1.10.4 --- Problems with Lipases --- p.26 / Chapter 1.11 --- Replacement of Sodium Salt in Food with Alternative Salts --- p.29 / Chapter 1.12 --- Objectives --- p.33 / Chapter 2 --- Development of Volatile Compounds in Sufu --- p.35 / Chapter 2.1 --- Introduction --- p.35 / Chapter 2.2 --- Materials and Method --- p.36 / Chapter 2.2.1 --- Sufu Production --- p.36 / Chapter 2.2.1.1 --- Preparation of Tofu --- p.36 / Chapter 2.2.1.2 --- Inoculation of Tofu --- p.37 / Chapter 2.2.1.2.1 --- The Mold Strain --- p.37 / Chapter 2.2.1.2.2 --- Spore Suspension --- p.38 / Chapter 2.2.1.2.3 --- Spore Count in Spore Suspension --- p.38 / Chapter 2.2.1.3 --- Preparation of Pehtze --- p.39 / Chapter 2.2.1.4 --- Brining and Aging --- p.41 / Chapter 2.2.2 --- Sampling of Sufu --- p.42 / Chapter 2.2.3 --- Flavor Analysis --- p.42 / Chapter 2.2.3.1 --- Simultaneous Steam Distillation-Solvent Extraction (SDE) --- p.42 / Chapter 2.2.3.2 --- Gas chromatography-mass spectrometry (GC-MS) Conditions --- p.43 / Chapter 2.2.3.3 --- Compound Identification and Quantification --- p.44 / Chapter 2.3 --- Results --- p.45 / Chapter 2.3.1 --- Evolution of Volatiles During Sufu Aging --- p.45 / Chapter 2.3.1.1 --- Esters --- p.46 / Chapter 2.3.1.2 --- Alcohols --- p.51 / Chapter 2.3.1.3 --- Aldehydes --- p.55 / Chapter 2.3.1.4 --- Ketones --- p.55 / Chapter 2.3.1.5 --- Other Nitrogen-containing Compounds --- p.59 / Chapter 2.3.1.6 --- Sulfur (S)-containing and Oxygen (O)-containing Compounds --- p.51 / Chapter 2.3.1.7 --- Pyrazines --- p.61 / Chapter 2.3.1.8 --- Miscellaneous Compounds --- p.63 / Chapter 2.3.2 --- Change in the Concentrations of Sufu Odorous Compounds with Time --- p.65 / Chapter 2.4 --- Discussion --- p.67 / Chapter 2.4.1 --- Quantitatively Important Volatile Components of Sufu --- p.67 / Chapter 2.4.2 --- Esters --- p.59 / Chapter 2.4.3 --- Alcohols --- p.72 / Chapter 2.4.3.1 --- 1-Hexanol --- p.72 / Chapter 2.4.3.2 --- Phenol and 2-Methoxyphenol --- p.74 / Chapter 2.4.4 --- Aldehydes --- p.75 / Chapter 2.4.4.1 --- Hexanal --- p.75 / Chapter 2.4.4.2 --- "(E,E)-2,4-Heptadienal" --- p.77 / Chapter 2.4.4.3 --- (E)-2-Heptenal --- p.78 / Chapter 2.4.4.4 --- Benzeneacetaldehyde --- p.79 / Chapter 2.4.5 --- Ketones --- p.80 / Chapter 2.4.5.1 --- 3-Hydroxy-2-Butanone --- p.81 / Chapter 2.4.6 --- Sulfur-Containing Compounds --- p.82 / Chapter 2.4.6.1 --- 3-(Methylthio)propanal --- p.82 / Chapter 2.4.7 --- Pentylfuran --- p.84 / Chapter 2.4.8 --- Naphthalene --- p.86 / Chapter 2.4.9 --- Contaminants and artifacts generated by A-SDE --- p.87 / Chapter 2.5 --- Conclusion --- p.92 / Chapter 3 --- Acceleration of Sufu Production with Exogenous Lipase Effect on Flavor Development --- p.95 / Chapter 3.1 --- Introduction --- p.95 / Chapter 3.2 --- Materials and Method --- p.96 / Chapter 3.2.1 --- Sufu Production --- p.96 / Chapter 3.2.2 --- The Addition of Lipases --- p.96 / Chapter 3.2.3 --- Sampling of Sufu --- p.97 / Chapter 3.2.4 --- Flavor Analysis --- p.97 / Chapter 3.2.5 --- Statistical Analysis of Sufu Flavor Compounds --- p.98 / Chapter 3.2.6 --- Proximate Analysis --- p.98 / Chapter 3.2.7 --- Freeze-Drying --- p.99 / Chapter 3.2.8 --- Statistical Analysis of Sufu Proximate Contents --- p.99 / Chapter 3.2.9 --- Sensory Evaluation of Experimental Sufu --- p.100 / Chapter 3.3 --- Results --- p.102 / Chapter 3.3.1 --- Experiment I ´ؤ Adding 0.01% (w/w) Lipase from Porcine Pancreas and Candida rugosa --- p.102 / Chapter 3.3.1.1 --- Esters --- p.104 / Chapter 3.3.1.2 --- Alcohols --- p.108 / Chapter 3.3.1.3 --- Aldehydes --- p.110 / Chapter 3.3.1.4 --- 3-Hydroxy-2-Butanone --- p.113 / Chapter 3.3.1.5 --- 3-(Methylthio)propanal --- p.114 / Chapter 3.3.1.6 --- 2-Pentylfuran --- p.115 / Chapter 3.3.1.7 --- Naphthalene --- p.115 / Chapter 3.3.2 --- Experiment II - Adding 0.02% Lipase from Porcine Pancreas and Candida rugosa --- p.117 / Chapter 3.3.2.1 --- Esters --- p.118 / Chapter 3.3.2.2 --- Alcohols --- p.123 / Chapter 3.3.2.3 --- Aldehydes --- p.125 / Chapter 3.3.2.4 --- 3-Hydroxy-2 -Butanone --- p.129 / Chapter 3.3.2.5 --- 3-(Methylthio)propanal --- p.129 / Chapter 3.3.2.6 --- 2-Pentylfuran --- p.131 / Chapter 3.3.2.7 --- Naphthalene --- p.131 / Chapter 3.3.3 --- Sensory Evaluation of Lipase-treated Sufu --- p.132 / Chapter 3.3.4 --- Proximate Composition of Sufu at Different Ages from the 3 Treatments --- p.134 / Chapter 3.3.4.1 --- Addition of 0.01%(w/w) Lipase to Sufu Aging Solution --- p.134 / Chapter 3.3.4.1.1 --- Crude Protein --- p.134 / Chapter 3.3.4.1.2 --- Crude Lipid --- p.135 / Chapter 3.3.4.1.3 --- Moisture --- p.138 / Chapter 3.3.4.1.4 --- Ash --- p.138 / Chapter 3.3.4.2 --- Addition of 0.02% (w/w) Lipase to Sufu Aging Solution --- p.141 / Chapter 3.3.4.2.1 --- Crude Protein --- p.141 / Chapter 3.3.4.2.2 --- Crude Lipid --- p.141 / Chapter 3.3.4.2.3 --- Moisture --- p.144 / Chapter 3.3.4.2.4 --- Ash --- p.144 / Chapter 3.4 --- Discussion --- p.147 / Chapter 3.4.1 --- Adding 0.01 % Lipase from Porcine Pancreas and Candida rugosa --- p.147 / Chapter 3.4.1.1 --- Comparison of Total Odorous Content --- p.147 / Chapter 3.4.1.2 --- Sensory Evaluation of Experimental Sufu --- p.147 / Chapter 3.4.2 --- Adding 0.02% Lipase from Porcine Pancreas and Candida rugosai --- p.150 / Chapter 3.4.2.1 --- Comparison of Total Odorous Content --- p.150 / Chapter 3.4.2.2 --- Sensory Evaluation of Experimental Sufu --- p.151 / Chapter 3.4.3 --- Summary of Sensory and TOC Results of Lipase Experiments --- p.153 / Chapter 3.4.4 --- Impact of Lipase Addition on Different Odorous Volatile Compounds --- p.153 / Chapter 3.4.4.1 --- Esters --- p.154 / Chapter 3.4.4.2 --- Alcohols --- p.155 / Chapter 3.4.4.3 --- Aldehydes --- p.157 / Chapter 3.4.4.4 --- 3-Hydroxy-2-Butanone --- p.159 / Chapter 3.4.4.5 --- 3-(Methylthio)propanal --- p.160 / Chapter 3.4.4.6 --- 2-Pentylfuran and Naphthalene --- p.161 / Chapter 3.4.5 --- Effect of Aging on Chemical Composition of Sufu --- p.161 / Chapter 3.4.5.1 --- Crude Protein --- p.161 / Chapter 3.4.5.2 --- Crude Lipid --- p.162 / Chapter 3.4.5.3 --- Ash --- p.163 / Chapter 3.4.6 --- Effect of Lipase Addition on Chemical Composition of Sufu --- p.163 / Chapter 3.4.7 --- Effect of Lipase Addition on Free Fatty Acid (FFA) Profiles --- p.164 / Chapter 3.4.8 --- Generation of Different Classes of Esters from Animal and Fungal Lipases --- p.168 / Chapter 3.5 --- Conclusion --- p.171 / Chapter 4 --- "Partial Substitution of Sodium Chloride with Potassium Chloride in Sufu Aging Solution - Effect on Proteolysis, Bacterial Growth and Flavor" --- p.174 / Chapter 4.1 --- Introduction --- p.174 / Chapter 4.2 --- Materials and Method --- p.175 / Chapter 4.2.1 --- Sufu Production --- p.175 / Chapter 4.2.2 --- Partial Substitution of NaCl with KC1 --- p.176 / Chapter 4.2.3 --- Sampling of Sufu --- p.176 / Chapter 4.2.4 --- Bacterial Count --- p.176 / Chapter 4.2.5 --- Total and Amino Nitrogen Contents in Sufu --- p.177 / Chapter 4.2.6 --- Sensory Evaluation of Experimental Sufu --- p.177 / Chapter 4.3 --- Results --- p.179 / Chapter 4.3.1 --- Microbial Growth --- p.179 / Chapter 4.3.2 --- Proteolysis --- p.181 / Chapter 4.3.2.1 --- Total Nitrogen Content (TN) --- p.181 / Chapter 4.3.2.2 --- Amino Nitrogen Content (AN) --- p.184 / Chapter 4.3.3 --- Sensory Evalutaion of Control and KCl-Substituted Sufu --- p.186 / Chapter 4.4 --- Discussion --- p.187 / Chapter 4.4.1 --- Microbial Growth --- p.187 / Chapter 4.4.2 --- Proteolysis --- p.189 / Chapter 4.4.3 --- Sensory Tests --- p.194 / Chapter 4.5 --- Conclusion --- p.198 / Chapter 5 --- Overal Conclusion --- p.199 / References --- p.204 / Appendix I --- p.228 / Appendix II --- p.229
20

Optimization of headspace solid-phase microextraction conditions for analyzing the volatile changes in a commercial plain sufu during its fermentation process. / CUHK electronic theses & dissertations collection

January 2012 (has links)
腐乳是中國傳統的黃豆發酵類製品,口感柔滑,風味獨特,與西方的芝士相似。多個世紀以來一直是中國的特色配菜和開胃小吃。以往對腐乳的研究只限於使用水蒸氣蒸餾法,溶劑抽提法,超臨界萃取法以及頂空萃取法提取其揮發性化合物,但它們卻有準備時間長、可能產生製造物、較低靈敏度、使用有機溶劑或需要精密的設備等的缺點。而固相微萃取方法(SPME)是集取樣、提取、濃縮三個步驟為一的提取方法。這是一個簡單、快速、溫和而且有相對靈敏度較高的方法。因此,這項研究的主要目標是開發一個快速的頂空固相微萃取方法,並配合氣相色譜-質譜聯用方法來提取和鑒定巿面上白腐乳的揮發性物質,並研究白腐乳整個發酵週期的理化的變化。 / 第一部份的研究首先對固相微萃取塗層(萃取頭),提取溫度,提取時間,鹽濃度和水含量等參數進行優化。優化條件的結果如下:(1)樣本對鹽溶液(NaCl溶液(25%飽和濃度))的比例為1:2(w/v),(2)用Divinylbenzene/Carboxen/ Polydimethylsiloxane 塗層的萃取頭,(3)在55°C的水浴進行30分鐘提取。 / 第二部份的研究是用氣相色譜-質譜聯用方法分析利用以上的方法提取的三種商業白腐乳的揮發性化合物。結果在三個樣品中共檢測出131揮發性化合物。樣品A、B和C,分別檢測出112、112和118種成份,他們均屬於不同的官能團。三種腐乳共有76種相同的化合物。其中包括11種由Chung等人於2005年確定的重要香味化合物。而醇類和酯類化合物的含量最為豐富。另外,許多酯類,醛類和芳香烴化合物都是首次在腐乳中發現的。總括而言,該部份實驗成功開發了一種廉價且溫和的提取技術,讓我們可以簡單及快速地從檢定出腐乳中多種揮發性化合物。 / 研究的最後部份是針對商業白腐乳在發酵(腐乳坯期)和老化(後加入紅酒和鹽水)時,揮發性化合物的種類及濃度和理化參數的變化進行了研究。結果顯示,主要的化學成分的濃度是在發酵及熟成過程中増加,同時新的化合物亦不斷地形成。由腐乳坯階段至36小時、60天、120天和180天的發酵期,分別有37、58、69、83和86種化合物形成。其中酯類及吡嗪佔大多數,其濃度亦不斷地增加。而且,大部份的重要香味化合物的濃度亦顯著地增加。另外,許多在黃酒和芝麻油檢測出來的揮發物也可以從腐乳中找到的。理化分析的結果顯示,水分含量沒有顯著變化,但蛋白質的含量在熟化期的首四個月顯著下降。相反,灰含量則在四個月顯著地增加。此研究為腐乳發酵和熟化過程中的揮發性成分和化學成分的變化提供了更多的資料,然而要進一步了解腐乳發酵對味道和口感的影響則需要更多感官測試方面的研究。 / Sufu is a traditional Chinese fermented product with a soft creamy cheese-like texture and a unique flavour. It has been widely consumed in China as an appetizer for centuries. Previous investigations on its volatile compounds using simultaneous steam distillation and solvent extraction (SDE), supercritical fluid extraction (SFE) or headspace extraction may suffer from drawbacks such as artifact formation, the use of organic solvents and the need for sophisticated equipment. An alternative Solid-phase Microextraction (SPME) method integrates sampling, extraction, concentration into a single step method. However, this technique is highly sensitive to experimental conditions, careful optimization would be required to ensure a good extraction performance. / Our primary objective in this study was to develop a quick volatile profiling method using the Headspace - Solid-phase Microextraction - Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS) for subsequent studies on commercial products and their changes throughout the fermentation and ageing periods. Parameters including stationary phase (fiber coating), extraction temperatures, exposure times, concentration of salt and water content were optimized. / The optimal conditions found using the Divinylbenzene/Carboxen/ Polydimethylsiloxane (DVB/CAR/PDMS) fiber for sufu sample are (1) sample to 25% of (saturated) NaCl solution is 1:2 (w/v), (2) 30 min of extraction time at 55°C water bath. / The developed method was applied to study the volatile profile of three commercial brands of plain sufu. In total, 131 volatile compounds were detected in the headspace of the examined samples. Samples A, B and C have totals of 112, 112 and 118 compounds, respectively, and they belong to various chemical groups. Seventy-six compounds were found in common among the commercial samples. These included 11 out of the 14 aroma-impact compounds previously identified by Chung et al., 2005. Quantitatively, alcohols and esters were among the most abundant groups of compound found. Many esters, aldehydes and aromatic hydrocarbons compounds were first reported in this study. The results obtained by SPME were comparable to those obtained by SFE and SDE methods and at the same time it is cheaper and less labor intensive method in terms of the extraction and clean-up steps. In short, the developed HS-SPME method is an inexpensive, simple, rapid and mild extraction technique which allows the detection of a wide range of volatiles from sufu. / In the final part of the study, the changes of volatile profile and the physicochemical parameters of a commercially produced plain sufu were studied throughout its fermentation (pehtze period) and ageing (after wine & brine added) processes. The volatile profiles of the key ingredients, namely, yellow rice wine and sesame seed oil were also studied. In general, all the major chemical groups experienced an increase in concentration during ageing. Many new compounds were formed in the first few months of ageing. A total of 37, 58, 69, 83 and 86 compounds were identified in pehtze stage, days 0 (36 hour since bottling), 60, 120 and 180, respectively. Esters and pyrazines account for most of the quality difference. Their concentrations increased throughout the ageing period. Concentration for most of the aroma-impact compounds increased significantly throughout ageing. Many of the volatiles detected in the yellow rice wine and the sesame oil were found in common with the ageing or matured sufus (6th month). Proximate analysis showed that there were no significant changes in moisture content but a significant decline in both the lipid, protein contents were observed. On the other hand, the ash content was significantly increased in the first four months, but leveled off afterwards. While this study provides some more information to understand the changes in both volatile components and chemical composition during the fermentation and ageing processes, further studies will be needed to explain the flavour and textural changes. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chiang, Tsz Kei Jackie. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 153-195). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Thesis Committee / Acknowledgements / Abstract --- p.I / 摘要 --- p.IV / Table of Contents --- p.VI / List of Tables --- p.XI / List of Figures --- p.XII / List of Abbreviations --- p.XIV / Chapter Chapter 1 --- Literature Review --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Sufu --- p.3 / Chapter 1.2.1 --- History and Background of Sufu --- p.3 / Chapter 1.2.2 --- Sufu Classification --- p.5 / Chapter 1.2.2.1 --- White Sufu --- p.5 / Chapter 1.2.2.2 --- Red Sufu --- p.5 / Chapter 1.2.2.3 --- Grey Sufu --- p.6 / Chapter 1.2.2.4 --- Other Types --- p.6 / Chapter 1.2.3 --- Manufacturing of Sufu --- p.7 / Chapter 1.2.4 --- Microbes Used in Sufu Fermentation --- p.10 / Chapter 1.2.5 --- Biochemical Changes during Sufu Ageing --- p.10 / Chapter 1.2.5.1 --- Protein Faction --- p.11 / Chapter 1.2.5.2 --- Lipid Fraction --- p.12 / Chapter 1.2.5.3 --- Carbohydrate Fraction --- p.12 / Chapter 1.2.6 --- Flavour Origin of Sufu --- p.13 / Chapter 1.2.7 --- Volatile Components of Sufu --- p.14 / Chapter 1.2.7.1 --- Alcohols --- p.14 / Chapter 1.2.7.2 --- Esters --- p.15 / Chapter 1.2.7.3 --- Aldehydes --- p.16 / Chapter 1.2.7.4 --- Furans --- p.17 / Chapter 1.2.7.5 --- Ketones --- p.17 / Chapter 1.2.7.6 --- Sulphur-containing Compounds --- p.18 / Chapter 1.2.8 --- Aroma-impact Compounds --- p.20 / Chapter 1.2.8.1 --- Aroma-impact Compounds in Sufu --- p.23 / Chapter 1.3 --- Flavor Extraction Techniques --- p.23 / Chapter 1.3.1 --- Headspace Methods --- p.24 / Chapter 1.3.1.1 --- Static Headspace Sampling --- p.25 / Chapter 1.3.1.2 --- Dynamic Headspace Sampling --- p.25 / Chapter 1.3.2 --- Solvent Extraction --- p.26 / Chapter 1.3.3 --- Steam Distillation Techniques --- p.27 / Chapter 1.3.3.1 --- Simultaneous Steam Distillation and Solvent Extraction (SDE) --- p.27 / Chapter 1.3.3.2 --- High-vacuum Distillation Techniques --- p.28 / Chapter 1.3.4 --- Supercritical Fluid Extraction Methods (SFE) --- p.28 / Chapter 1.3.5 --- Solid-phase Extraction (SPE) --- p.30 / Chapter 1.3.6 --- Solid-phase Microextraction (SPME) --- p.31 / Chapter 1.4 --- Objectives --- p.35 / Chapter Chapter 2 --- Optimization of Headspace Solid-phase Microextraction Conditions for the Determination of Volatile Compounds in Sufu --- p.36 / Chapter 2.1 --- Introduction --- p.36 / Chapter 2.2 --- Materials and Methods --- p.40 / Chapter 2.2.1 --- Materials --- p.40 / Chapter 2.2.1.1 --- Commercial Plain Sufu --- p.40 / Chapter 2.2.1.2 --- SPME Accessories --- p.40 / Chapter 2.2.2 --- Sample Preparation --- p.41 / Chapter 2.2.3 --- Optimization of Sample Preparation Method for HS-SPME-GC/MS Analysis --- p.41 / Chapter 2.2.3.1 --- Effect of Ionic Strength (NaCl Concentration) --- p.42 / Chapter 2.2.3.2 --- Optimization of Water Content --- p.42 / Chapter 2.2.4 --- Optimization of the Extraction Conditions for HS-SPME- GC/MS Analysis --- p.42 / Chapter 2.2.4.1 --- HS-SPME Procedures --- p.43 / Chapter 2.2.5 --- Gas Chromatography/Mass Spectrometry (GC/ MS) Conditions --- p.43 / Chapter 2.2.6 --- Identification and Quantification of Selected Volatiles in Sufu --- p.44 / Chapter 2.3 --- Results and Discussions --- p.46 / Chapter 2.3.1 --- Method Development --- p.46 / Chapter 2.3.1.1 --- Choice of Fibers --- p.46 / Chapter 2.3.1.2 --- Effect of Time --- p.48 / Chapter 2.3.1.3 --- Effect of Temperature --- p.49 / Chapter 2.3.1.4 --- Effect of Ionic Strength (NaCl Concentration) --- p.51 / Chapter 2.3.1.5 --- Effect of Water Content --- p.52 / Chapter 2.3.2 --- Application of the HS-SPME-GC/MS Method for the Analysis of Sufu Volatiles --- p.61 / Chapter 2.3.2.1 --- Alcohols --- p.62 / Chapter 2.3.2.2 --- Aldehydes --- p.63 / Chapter 2.3.2.3 --- Aliphatic Hydrocarbons --- p.64 / Chapter 2.3.2.4 --- Aromatic Hydrocarbons --- p.65 / Chapter 2.3.2.5 --- Esters --- p.67 / Chapter 2.3.2.6 --- Furans --- p.69 / Chapter 2.3.2.7 --- Ketones --- p.70 / Chapter 2.3.2.8 --- Pyrazines --- p.71 / Chapter 2.3.2.9 --- Sulphur-containing Compounds --- p.73 / Chapter 2.3.3 --- Comparison of Different Extraction Techniques --- p.74 / Chapter 2.4 --- Conclusion --- p.86 / Chapter Chapter 3 --- Changes in Volatile Constituents and Physicochemical Characteristics of Commercial Plain Sufu throughout the Fermentation and Ageing Process --- p.87 / Chapter 3.1 --- Introduction --- p.87 / Chapter 3.2 --- Materials and Methods --- p.90 / Chapter 3.2.1 --- Sufu Sampling --- p.90 / Chapter 3.2.2 --- Flavour Analysis --- p.90 / Chapter 3.2.2.1 --- Sample Preparation --- p.90 / Chapter 3.2.2.2 --- Solid-phrase Microextraction (SPME) --- p.91 / Chapter 3.2.2.3 --- Gas Chromatography/ Mass Spectrometry (GC/ MS) Conditions --- p.92 / Chapter 3.2.2.4 --- Identification and Quantification of Selected Volatiles in Sufu --- p.93 / Chapter 3.2.3 --- Proximate Analysis --- p.93 / Chapter 3.2.4 --- Statistical Analysis --- p.94 / Chapter 3.3 --- Results and Discussions --- p.95 / Chapter 3.3.1 --- Overall Finding --- p.95 / Chapter 3.3.2 --- Flavour Analysis of Sufu at Different Fermentation and Ageing Stages --- p.97 / Chapter 3.3.2.1 --- Alcohols --- p.97 / Chapter 3.3.2.2 --- Aldehydes --- p.99 / Chapter 3.3.2.3 --- Esters --- p.101 / Chapter 3.3.2.4 --- Furans --- p.104 / Chapter 3.3.2.5 --- Ketones --- p.105 / Chapter 3.3.2.6 --- Pyrazines --- p.107 / Chapter 3.3.2.7 --- Sulphur-containing Compounds --- p.108 / Chapter 3.3.2.8 --- Miscellaneous Compounds --- p.110 / Chapter 3.3.2.9 --- Aroma-impact Compounds --- p.111 / Chapter 3.3.3 --- Potential Volatile Flavour Contributors from the Key Ingredients (Yellow Rice Wine and Sesame Seed Oil) --- p.112 / Chapter 3.3.3.1 --- Volatile Compounds in Yellow Rice Wine --- p.113 / Chapter 3.3.3.2 --- Volatile Compounds in Sesame Seed Oil --- p.114 / Chapter 3.3.4 --- Proximate Composition of Sufu at Different Fermentation and Ageing Stages --- p.115 / Chapter 3.3.5 --- Overall Discussion --- p.144 / Chapter 3.4 --- Conclusion --- p.146 / Chapter Chapter 4 --- OverallConclusion --- p.148 / Chapter 4.1 --- Conclusions and Significance of the Study --- p.148 / Chapter 4.2 --- Future Work --- p.151 / References --- p.153 / Chapter Appendix A --- p.196 / Chapter Appendix B --- p.199

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