福州大学2006~2007学年第二学期考试A卷 课程名称Food Chemistry 考试日期June28.2007 考生姓名 学号 专业或类别 题号 三 四 五 六 七 总分 累分人 100 签名 题分 得分 考生注意事项：1、本试卷共9页，请查看试卷中是否有缺页。 2、考试结束后，考生不得将试卷、答题纸和草稿纸带出考场。 选择题（每小题1.5分，共22.5分） 得分评卷人 1.In general,which of the following is NOT expected to increase as water activity increases?() a)lipolysis reaction rates b)Carbohydrate hydrolysis reaction rates c)Microorganism growth d)All ofthe above would be expected to increase Why are Maillard reactions slower at high water activities?( a)Because Maillard reactions are hydrolysis reactions b)Because polyphenol oxidase is inactive at high water activities c)Because all the brown pigments dissolve away at high water activities d)Because water is an initial product of Maillard browning 3.When a food of low water activity is sealed in the same package as a food of high water activity what will occur over time?( a)Moisture will migrate from the low water activity food to the high water activity food b)Moisture will not migrate in either direction c)The high water activity food will increase in moisture content d)Answer a and c will occur e)Moisture will migrate from the high water activity food to the low water activity food 第1页共9页
第 1 页 共 9 页 福州大学 2006～2007 学年第二学期考试 A 卷 课程名称 Food Chemistry 考试日期 June 28, 2007 考生姓名 学号 专业或类别 题号 一 二 三 四 五 六 七 八 总分 题分 100 累 分 人 签名 得分 考生注意事项：1、本试卷共 9 页，请查看试卷中是否有缺页。 2、考试结束后，考生不得将试卷、答题纸和草稿纸带出考场。 一、 选择题(每小题 1.5 分，共 22.5 分) 得分 评卷人 1. In general, which of the following is NOT expected to increase as water activity increases? （ ） a) Lipolysis reaction rates b) Carbohydrate hydrolysis reaction rates c) Microorganism growth d) All of the above would be expected to increase 2. Why are Maillard reactions slower at high water activities? （ ） a) Because Maillard reactions are hydrolysis reactions b) Because polyphenol oxidase is inactive at high water activities c) Because all the brown pigments dissolve away at high water activities d) Because water is an initial product of Maillard browning 3. When a food of low water activity is sealed in the same package as a food of high water activity what will occur over time? （ ） a) Moisture will migrate from the low water activity food to the high water activity food b) Moisture will not migrate in either direction c) The high water activity food will increase in moisture content d) Answer a and c will occur e) Moisture will migrate from the high water activity food to the low water activity food
4.Sucrose would participate in which of the following reactions?( a)An oxidation test b)Maillard browning c）Caramelization d)Enzymatic browning e)Sucrose would participate in all of the above 5. Which of the following is a good strategy for preventing Maillard browning?( a)Removing reducing sugars b)Adding PPO c)Adding alcohol d)Answer a and b e)Answer a,b and c 6.Which of the following sugars is the least sweet at room temperature?( a)Fructose b)Lactose c)Sucrose d)Glucose e)D-Fructopyranose 7.Pectin is(） a)a polysaccharide of galacturonic acid and galcturonic acid derivatives subunits b)a polysaccharide of glucose subunits c)a protein rich in proline and proline derivatives d)a supplement for building up pectoral muscles e)all of the above 8.Gelatin is obtained from ( a)seaweed b)fruit c)derivatized cellulose d)collagen from animals 9.Above the gelatinization temperature ( a)collagen turns to gelatin b)starch granules lose their crystallinaty c）pectin forms a gel d)amylopectin becomes insoluble in water and precipitates e)none of the above 10.During lipid digestion,fatty acids are most likely cleaved from what positions?( a)sn-1 and sn-3 b)sn-1 and sn-2 c)sn-2 and sn-3 d)sn-2 only e) sn-4 第2页共9页
第 2 页 共 9 页 4. Sucrose would participate in which of the following reactions? （ ） a) An oxidation test b) Maillard browning c) Caramelization d) Enzymatic browning e) Sucrose would participate in all of the above 5. Which of the following is a good strategy for preventing Maillard browning? （ ） a) Removing reducing sugars b) Adding PPO c) Adding alcohol d) Answer a and b e) Answer a, b and c 6. Which of the following sugars is the least sweet at room temperature? （ ） a) Fructose b) Lactose c) Sucrose d) Glucose e) DFructopyranose 7. Pectin is （ ） a) a polysaccharide of galacturonic acid and galcturonic acid derivatives subunits b) a polysaccharide of glucose subunits c) a protein rich in proline and proline derivatives d) a supplement for building up pectoral muscles e) all of the above 8. Gelatin is obtained from （ ） a) seaweed b) fruit c) derivatized cellulose d) collagen from animals 9. Above the gelatinization temperature （ ） a) collagen turns to gelatin b) starch granules lose their crystallinaty c) pectin forms a gel d) amylopectin becomes insoluble in water and precipitates e) none of the above 10. During lipid digestion, fatty acids are most likely cleaved from what positions? （ ） a) sn1 and sn3 b) sn1 and sn2 c) sn2 and sn3 d) sn2 only e) sn4
11.Which of the following is a major difference between lard and cocoa butter?( a)Cocoa butter melts at a much lower temperature than does lard b)Cocoa butter is much higher in fat than lard c)Cocoa butter has a much narrower melting range than does lard d)Cocoa butter has very different types of fatty acid groups than does lard e)None of the above 12.Why would soybean oil be hydrogenated?( a)To increase its melting point b)To make it more solid at room temperature c)To protect it from oxidation d)Answer a and bonly e)Answer a,b and c 13.Which ofthe following triglycerides would melt at the owest temperature?( a)Triglycerides containing palmitic acid(16:0)groups only b)Triglycerides containing cis oleic acid(18:1)groups only c)Triglycerides containing trans oleic acid(18:1)groups only d)Triglycerides containing stearic acid(18:0)groups only 14.Hydrolysis of proteins leads to ( a)an increase in the hydrophobic character of amino acids b)oxidation of peptides c)cleavage of peptide bonds d)answer a and c e)none of the above 15.Which of the following is an emulsion?( a)a dispersion of sugar in water b)a dispersion of oil in water c)a solution of protein in water d)a dispersion of solid peanuts in peanut oil? 二、判断题（正确的打“√”，错误的“×”，每小题1.5分，共7.5分） 得分评卷人 1. Lysozyme is one of the major proteins ofegg yolk. () Phosvitin is a kind of protein from egg yolk. () 3. Soy protein has four major globular proteins:2S,7S,11S,15S.() Peanut protein is short oftwo amino acids(Met and Trp) () 5.Benzoic acid exhibits optimum activity in the pH above 7. () 第3页共9页
第 3 页 共 9 页 11. Which of the following is a major difference between lard and cocoa butter? （ ） a) Cocoa butter melts at a much lower temperature than does lard b) Cocoa butter is much higher in fat than lard c) Cocoa butter has a much narrower melting range than does lard d) Cocoa butter has very different types of fatty acid groups than does lard e) None of the above 12. Why would soybean oil be hydrogenated? （ ） a) To increase its melting point b) To make it more solid at room temperature c) To protect it from oxidation d) Answer a and b only e) Answer a, b and c 13. Which of the following triglycerides would melt at the lowest temperature? （ ） a) Triglycerides containing palmitic acid (16:0) groups only b) Triglycerides containing cis oleic acid (18:1) groups only c) Triglycerides containing trans oleic acid (18:1) groups only d) Triglycerides containing stearic acid (18:0) groups only 14. Hydrolysis of proteins leads to （ ） a) an increase in the hydrophobic character of amino acids b) oxidation of peptides c) cleavage of peptide bonds d) answer a and c e) none of the above 15. Which of the following is an emulsion? （ ） a) a dispersion of sugar in water b) a dispersion of oil in water c) a solution of protein in water d) a dispersion of solid peanuts in peanut oil? 二、判断题(正确的打“÷” ，错误的“¥” ，每小题 1.5 分，共 7.5 分) 得分 评卷人 1. Lysozyme is one of the major proteins of egg yolk. （ ） 2. Phosvitin is a kind of protein from egg yolk. （ ） 3. Soy protein has four major globular proteins: 2S, 7S, 11S, 15S.（ ） 4. Peanut protein is short of two amino acids (Met and Trp) （ ） 5. Benzoic acid exhibits optimum activity in the pH above 7. （ ）
三、填空题（每空格1分，共12分） 得分评卷人 1.Important factors governing the stability of foods during handling,processing,and storage are and so on. 2.Starch granules are composed of a mixture of two polymers:an essentially linear polysaccharide called _and a highly branched polysaccharide called Flavor consists of five dimensions,which are and 四、问答题（共42分） 得分评卷人 Question 1(9 points) (a)Describe the three steps involved in Maillard reaction in detail.(3 points) (b)Give three examples of where this reaction occurs in foods,and whether they are favourable((受欢迎的)or unfavourable.(6 points)) 第4页共9页
第 4 页 共 9 页 三、填空题(每空格 1 分，共 12 分) 得分 评卷人 1. Important factors governing the stability of foods during handling, processing, and storage are , , , , , and so on. 2. Starch granules are composed of a mixture of two polymers: an essentially linear polysaccharide called , and a highly branched polysaccharide called . 3. Flavor consists of five dimensions, which are , , , and . 四、问答题(共 42 分) 得分 评卷人 Question 1 (9 points) (a) Describe the three steps involved in Maillard reaction in detail. (3 points) (b) Give three examples of where this reaction occurs in foods, and whether they are favourable(受欢迎的) or unfavourable. (6 points)
Question 2(8 points) Describe protein gelation by discussing the following: (a)What is a protein gel?(full description required):(2 points) (b)The two-step process involved the formation of protein gels;(2 points) (c)The 4 factors that affect protein gelation.(4 points) 第5页共9页
第 5 页 共 9 页 Question 2 (8 points) Describe protein gelation by discussing the following: (a) What is a protein gel? (full description required); (2 points) (b) The twostep process involved the formation of protein gels; (2 points) (c) The 4 factors that affect protein gelation. (4 points)
Question 3(11 points) Autoxidation of Lipids-discuss the following aspects: (a)The three steps involved in the autoxidation of lipids?(3 points) (b)List four ways to reduce the extent of lipid oxidation,and briefly describe why each of them works.(8 points) 第6页共9页
第 6 页 共 9 页 Question 3 (11 points) Autoxidation of Lipids discuss the following aspects: (a) The three steps involved in the autoxidation of lipids? (3 points) (b) List four ways to reduce the extent of lipid oxidation, and briefly describe why each of them works. (8 points)
Question 4(10 points) (a)What are the changes in the colour of the green vegetables after long time cooking?And why?(4 pts) (b)According to the two figures,give a brief explanation to the effects of heat and pH on color stability of Anthocyanins.(6 pts) Ab orbance Spectrum of Cranberries 120180240 卓8年88层名會目 Time (min) Effect of temperature on colour stability of Effect of pH on colour stability anthocyanin (100 mg/100ml). (absorbance)of Anthocyanins 020C,▣50C,·750C,■100C 第7页共9页
第 7 页 共 9 页 Question 4 (10 points) (a) What are the changes in the colour of the green vegetables after long time cooking? And why? (4 pts) (b) According to the two figures, give a brief explanation to the effects of heat and pH on color stability of Anthocyanins. (6 pts) Effect of pH on colour stability (absorbance) of Anthocyanins Effect of temperature on colour stability of anthocyanin (100 mg/100ml). o 20 o C, p50 o C, · 75 o C, n 100 o C
Question 5(4 pts) Why calcium propionate could be as the major usage in bread and baked foods?Show the reasons in detail. 五、论述题（共16分） 得分评卷人 ESSAY SECTION (16 pts.): Please write at least 150 words(can be a little longer if necessary)in response to the topic below.Your response should,as clearly and completely as possible within the space constraints.be designed to educate a colleague on the properties of the requested food.And describe the effect ofeach ingredient on the quality attributes of the food in detail. The following is the list of ingredients in FUMA soft sandwich cake Fresh egg,refined flour,sugar,vegetable shortening oil,whole milk powder,sorbitol 糖醇)，maltitol(麦芽糖醇)，refined vegetable oil,.emulsifying agent,.edible alcohol,.raising agent ()thickening agent,edible salt,orange essence,flavoring agent,B-carotene. sodium dehydroacetate,natamycin(那他霉素)，colorant 第8页共9页
第 8 页 共 9 页 Question 5 (4 pts) Why calcium propionate could be as the major usage in bread and baked foods? Show the reasons in detail. 五、论述题(共 16 分) 得分 评卷人 ESSAY SECTION (16 pts.): Please write at least 150 words (can be a little longer if necessary) in response to the topic below. Your response should, as clearly and completely as possible within the space constraints, be designed to educate a colleague on the properties of the requested food. And describe the effect of each ingredient on the quality attributes of the food in detail. The following is the list of ingredients in FUMA soft sandwich cake: Fresh egg, refined flour, sugar, vegetable shortening oil, whole milk powder, sorbitol（山梨 糖醇）, maltito（麦芽糖醇） l , refined vegetable oil, emulsifying agent, edible alcohol, raising agent（膨松剂 ）thickening agent, edible salt, orange essence, flavoring agent, bcarotene, sodium dehydroacetate, natamycin(那他霉素), colorant
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