課程名稱︰生物材料分析
課程性質︰必修
課程教師︰賴喜美
開課學院：生物資源暨農學院
開課系所︰農業化學系
考試日期（年月日）︰2009年11月09日
考試時限（分鐘）：130分鐘
是否需發放獎勵金：Yes!!
（如未明確表示，則不予發放）
試題 :
1. 比較下列三種測水分的方法：
┌─────┬──────┬──────┬──────┐
│ │Forced draft│ Microwave │ Vaccum │
│ │ oven │ oven │ oven │
├─────┼──────┼──────┼──────┤
│ 重複1 │ 36.4 │ 35.7 │ 34.3 │
├─────┼──────┼──────┼──────┤
│ 重複2 │ 36.3 │ 36.2 │ 34.4 │
├─────┼──────┼──────┼──────┤
│ 重複3 │ 36.5 │ 36.4 │ 34.5 │
├─────┼──────┼──────┼──────┤
│ 重複4 │ 36.4 │ 37.2 │ 34.4 │
├─────┼──────┼──────┼──────┤
│ 平均值 │ 36.4 │ 36.5 │ 34.4 │
├─────┼──────┼──────┼──────┤
│ 標準差 │ 0.1 │ 0.3 │ 0.1 │
└─────┴──────┴──────┴──────┘
(1) Which method is more precise? Why?
Which method is more accurate? Why?
(2) 請以平均值 ±標準差的型式表示Microwave oven的數值，以Q-test判斷有
沒有可刪去的數值
(3) 計算 Force drafted oven method 的 coefficient of variation.
(4) 若真實值為34.5%，請討論Force drafted oven和Microwave數值偏高的原因
並比較這三種方法的優缺點
2.下表為某麵包的食品分析數據(in 100g)：
total fat 13g
saturated fat 5g
trans fat 3g
sodium 550mg
protein 0g
carbohydrate 31g
dietary fiber 5g
sugar 12g
(1)試以每份30g，共三份，作出標準的營養標示
(2)是否可以宣稱低脂? 高纖? 零蛋白質?
(PS.前兩題數字都是憑記憶來的，重點是題型，題目原文皆為英文)
3.In each case specified below, would you likely overestimate or under-
estimate the moisture content of a food product beung tested? Explain
your answer.
a. Forces draft oven
(Ⅰ) partical size too large
(Ⅱ) high concentration of volatile flavor compounds present
(Ⅲ) sample very hygroscopy
(Ⅳ) lipid oxidation
(Ⅴ) surface crust formation
b. Karl Fischer method
(Ⅰ) very humid day when weighing original samples
(Ⅱ) sample ground coarsely
(Ⅲ) food high in viamin C
(Ⅳ) food high in unsaturates fatty acid
c. Toluene distillation
(Ⅰ) emulsion between water in sample and solvent no broken
4.You are determining the total ash content of a product using the con-
ventional dry ashing method. Your boss asks you to switch to a conven-
tional wet ashing method because he has heard it takes less time than
dry ashing.
(1) Do you agree or disagree with your boss concerning the time issue,
and why?
(2) Not considering the time issues, why might tou want to continue
using dry ashing, and why might you change to wet ashing?
5.You performed fat analysis on a new super-energy shake (high carbo-
hydrate and protein) using standard Soxhlet extraction. The value
obtained for fat content was much lower than expected. What could have
caused the measured fat content to be low and how would you modify the
standard procedure to correct the problem?
6.The Munson-Walker, Lane-Eynon, and Somogyi-Nelson methods can be used
to measure reducing sugars. Explain the similarities and differences
among these methods with regard to the principles involved and the pro-
cedures used.
7.Compare and contrast the AOAC method and the Englyst-Cummings method
for determination of total dietary fiber. Consider the principles, pro-
cedures, applications, advantages, and disadvantages.
8.Below are four values for the fiber content (percent dwb) of wheat bran.
Using your knowledge of methods to measure crude fiber, acid-detergent
fiber, neutral-detergent fiber (with amylase), and the AOAC method for
total dietary fiber, indicate which method most likely fits with each
of the four values below. Justify your answer by listing the constituent
measured by each method.
---------------------------------------------------------------------
Precent Fiber Method Constituents Measured Procedure
---------------------------------------------------------------------
46.0
8.9
40.2
11.9
---------------------------------------------------------------------
9.A sample (5.0g) of food grade oil was reacted with excess KI to deter-
mine peroxide value. The free iodine was titrated with a standardized
solution of 0.10N Na2S2O3. The amount of titrant required was 0.60 mL
(blank corrected). Calculate the peroxide value of the oil.
10.Your analysis of an oil sample gives the following results. What does
each of these results tell you about the characterstics of the sample?
Briefly describe the principle for each method used:
a. large saponification value
b. low iodine value
c. high TBA number
d. high OSI
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