Food processing and preservation Quiz – 10


Q. For smoking of meat, generally saw dust or hardwood is burned at the temperature of _____________C

  1. 200
  2. 250
  3. 121
  4. 300

Answer: d)

When burned, the cellulose and hemicellulose in hardwoods produce sweet, flowery and fruity aromas. Products of pyrolysis of lignin include spicy, pungent phenolic compounds such as guaiacol, responsible for the smoky taste, phenol, and syringol, a contributor to a smoky aroma. Pyrolysis also produces sweeter aromas including vanilla-scented vanillin and clove-like isoeugenol (Hui, 2001; Guillén et al., 2006). Wood also contains small quantities of proteins that contribute roasted flavours. Lesimple et al. (1995) identified 62 volatile components in smoked duck fillets, including phenols, alcohols, ethers, aldehydes, ketones, hydrocarbons, acids, esters and terpenes, 34 of which were related to the smoking process. Others (CECEFS, 1992) report >400 volatile chemical compounds identified in wood smoke.

Different species of tree have different amounts of these components and hence their woods impart different flavours to food. The chemical composition, and hence the flavours in smoke, also depend on the temperature of the fire, the moisture content of the wood, the supply of air to the fire and any water added during burning. High-temperature fires break down flavour molecules into unpleasant-tasting compounds.

The optimal conditions for producing desirable smoke flavours are lower temperature, smouldering fires at 300–400°C. Woods that contain high amounts of lignin burn hotter and a restricted air supply is needed to keep them smouldering, or their moisture content is increased by soaking the pieces in water.

The factors that influence absorption of smoke by food include the density of the smoke, its humidity and temperature (see Section 14.1), and the moisture content of the food. The higher the smoke density, the greater the absorption. 

Q. ___________ will affect the growth and activity of microorganisms and enzymes 

  1. Heat
  2. Moisture
  3. Air
  4. All of the options

Answer: d)

Heat, moisture, air and humidity affect the growth of microorganism.

Q. The hotness of an object is determined by its __________.

  1. Temperature
  2. Humidity
  3. Both a and b
  4. None of the above

Answer: a)

Temperature is used to measure the hotness of an object.

Q. Temperature is measured in degree ______________.

  1. Fahrenheit
  2. Celsius
  3. Rankine
  4. ALL of the above

Answer: D)

Q. Pasteurization is the process of heating milk

  1. above 121C
  2. above the boiling point 
  3. below boiling point
  4. above 150C

Answer: c)

The term “Pasteurization”, “Pasteurised” and similar terms shall be taken to refer to the process of heating every particle of milk of different classes to at least 630C (sixty three degree centigrade) and holding at such temperature continuously for at least 30 minutes or heating it to at least 71.50C  (seventy one point five degree centigrade) and holding at such temperature continuously for at least 15 seconds or an approved temperature time combination that will serve to give a negative Phosphatase test.

All pasteurised milk of different classes shall be cooled immediately to a temperature of 100C, or less. (Less than 10 degree centigrade)

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