Which kinds of food products that rely on foam forming property of proteins?. How do proteins stabilize the foam?. 0.2 By forming flexible, cohesive films around the gas bubbles and ther
Trang 1TRƯỜNG ĐH SƯ PHẠM KỸ THUẬT TPHCMNG ĐH S PH M KỸ THU T TPHCMƯ ẠM KỸ THUẬT TPHCM ẬT TPHCM
KHOA CN Hóa H c & Th c Ph m ọc & Thực Phẩm ực Phẩm ẩm
B MÔN CN Th c Ph m Ộ MÔN CN Thực Phẩm ực Phẩm ẩm
ĐÁP ÁN Đ THI CU I KỲ H C KỲ II NĂM Ề THI CUỐI KỲ HỌC KỲ II NĂM ỐI KỲ HỌC KỲ II NĂM ỌC KỲ II NĂM
H C 2015 - 201 ỌC KỲ II NĂM 6 Môn: Anh văn chuyên ngành – Th c Ph mực Phẩm ẩm
Mã môn h c: FENG223950ọc: FENG223950
Đ 01 Ề THI CUỐI KỲ HỌC KỲ II NĂM Passage 01 (4/10)
1 What are proteins? (0.2)
Proteins are polymers of amino acid are formed through amide linkages
2 How many structures do proteins have? What are they? (0.2)
Proteins have four structure, including primary, secondary, tertiary and quaternary structures
3 What can be considered as causes of protein denaturation? (0.2)
Treatments that cleave hydrogen bridges, ionic or hydrophobic bonds are considered to cause protein denaturation
4 Which chemical linkages are formed in irreversible denaturation? (0.2)
Disulfide bonds
5 Which factors that influence the solubility of proteins? (0.2)
Factors that influence the solubility of proteins are the number of polar and a-polar groups and their arrangement along the molecule
6 Which kinds of food products that rely on foam forming property of proteins? (0.2)
Baked goods, sweets, desserts and beer
7 How do proteins stabilize the foam? (0.2)
By forming flexible, cohesive films around the gas bubbles and therefore reduce the surface tension, proteins stabilize the foam
8 How many phases are required to form protein gel? (0.2)
02 phases
9 What are the properties of polymeric network gel? (0.2)
Trang 2Low polymer concentration (∼1%), transparency and fine texture, gel formation is caused by setting a certain pH, by adding certain ions, or by heating/cooling, thermo-reversible
10 What is “thermo-reversible”? (0.2)
Thermo-reversible is the ability to reverse to its original structure when the temperature changes
11 Yes; 12 No; 13 Yes; 14 Yes; 15 Yes; 16 No; 17 No; 18 No; 19 No; 20 Yes
Passage 02 (3/10)
Short description of Tara-gum (maximum 70 words)
Tara Gum is a Galactomannan, natural thickener, emulsifier and stabilizer obtained from the milling of the endosperm of the seeds of Tara tree Tara gum has synergistic effects when used
in combination with kappa-carrageenan, Xanthan gum and agar, comparable to LBG Tara gum increases gel strength and makes the gel less prone to syneresis or produces long-term suspensions when combined with Agar and Carrageenan, and Xanthan gum, respectively
Comparison of Tara-gum with other additives
Constituents
identification
Mannose:galactose is 3:1 Mannose:galactose is 3:1
Color powder
identification
White to cream, odorless White to brown, characteristic odor
Color solution
identification
Translucent, soluble up to 55 Brix White to yellow, soluble just 35
Brix Gel test - Producing strong gel in
combination with Carrageenan
- Forming well with Xanthan Gum
- Not producing strong gel
- Not forming gel with Xanthan gum
Stability in
frozen and
defrozen products
Granulometry
test
Aerobics plate
count
Trang 3Gummy texture Gummy Without gummy
Passage 03 (3/10)
In this study, three probiotic species including Lactobacillus acidophilus, Bacillus
clausii and Saccharomyces boulardii were coated by “hydrogel” encapsulation technique
with sodium alginate (single layer) or combination of sodium alginate and gelatin (double layer) The free and encapsulated probiotic cells were subsequently inoculated in gastro-intestinal media for 120 min to examine the protective benefits of the layers The results
indicated that free L acidophilus and B clausii were completely inactivated after 60 and 90
min incubated at low pH condition respectively Single-layer encapsulation lengthened survival of both bacterial species by 30 min while those encapsulated by double layers were unaffected (in term of viable cell density) Free yeast showed better acid tolerance than bacteria with more than 10^3 viable cells after 120 min prolonged under pH 2.0 The viable cell density of yeast encapsulated by single layer decreased gradually during the inoculation but with a lower death rate compared to that of the free yeast Double-layer encapsulation, however, significantly improved survivability of the yeast and no reduction in viable cell density of the yeast was observed for 120 min Tolerance of the three species under intestinal condition followed the similar pattern to that under gastric condition SEM pictures of alginate-microbeads encapsulated probiotics demonstrated that the improvement in intolerance of probiotics to gastro-intestinal conditions was due to the protection of encapsulating molecules against external inhibition