1. Stereospecific analysis of triacylglycerides present in fat and oil:

Is used to distinguish between positional isomers
Is performed subjecting the material to a series of chromatographic separations
Uses a protease and an esterase
Resorts to phosphorilation

2. Even numbered straight chain fatty acids outnumber odd numbered and branched fatty acids in oils and fats:

Because they have higher melting points
Because they have lower melting points
Because their biosynthesis is more common
Because they yield stabler tryacylglycerols

3. Hydrogenation of an oil:

Generaly precedes deodorisation.
Is a homogeneous reaction
Can not yield trans isomers of fatty acids originally present
May yield trans fatty acids with migrated double bonds

4. Interesterification of oil blends:

Always yields some diacylglycerol as by-product
Yields triacylglycerol mixtures with narrow transition temperature range.
Will invariably lead to some cis-trans isomerisation
Must be performed at temperatures above 100 º C.

5. Oil in water emulsions:

Are more easily oxidisable than the oils they are made from
Are stable polydispersed systems
Invariably consist of a more abundant continuous phase with a minor component in a dispersed phase
Will act as dielectrics.

6. Phospholipase A2 is an enzyme which:

Cleaves the bond between phosphorus and glycerol oxygen.
Cleaves the bond between phosphorus and the alkylammonium.
Cleaves the bond to the acyl group in position 2.
Cleaves the bond to the acyl group in position 1.

7. Autoxidation rate:

Is not affected by light.
Depends from lipases present.
Will not be proportional to oxygen concentration.
Will remain constant at a given temperature.

8. Photoxidation:

Is much slower than autoxidation
Results in more different hydroperoxides than autoxidation
Results in less different hydroperoxides than autoxidation
Yields exactly the same hydroperoxides than autoxidation, in different amounts.

9. Phenolic antioxidants:

May be more efficient at high temperatures
Are better than other antioxidants
May enhance oxidation (determined by its concentration)
Are feared to be carcinogenic, except natural ones.

10. Enzyme degradation of oil:

May yield coloured products
Is the major cause of rancidity of virgin olive oil
Only happens in presence of oxygen
May enhance aroma and taste attributes

11. Enzymatic Analysis of Food:

Is the use of any analytical method for the detection of any particular enzyme activity.
Is the use of purified enzymes to quantify any compound (enzyme substrate) in a food sample.
Can be used to determine with accuracy any compound of interest.
There are limitations of direct enzymatic analysis with respect to the analysis of certain compounds.

12. Enzymatic Rapid Methods of Analysis:

Never are used as reference methods, because they lack precision and accuracy.
Never are used in the control laboratories in food industries, because they are very expensive.
Are commonly used to identify eventual incorrect thermal treatments in food products.
Are those that take less than 15 minutes for the quantitative determination.

13. Enzyme Immuno Assays:

ELISAs are all the assays that result from the combination of the enzymatic and the immunological techniques of analysis. Those assays where named after the scientist who invented them.
In ELISA assays the separation of the antibody-enzyme conjugate, bound to the antigen adsorbed to a solid matrix, from the free enzyme-antibody conjugate is essential to obtain a reliable quantitative result.
ELISA assays always develop in homogeneous media where the antibody-enzyme conjugate links to the antigen in the sample.
In enzyme immunoassays the choice of the enzyme to link to the proper antibody, that links to the component under analysis (antigen), is always directed to those that catalyse a fluorogenic reaction, in order to increase the sensitivity of the analysis.

14. The ATP (adenosine triphosphate) assay is an enzymatic analytical method that is based on the emission of light of an activated luciferin-luciferase complex of AMP (adenosine monophosphate):

It is used for the detection of eventual foodborne pathogens.
All the light emitted in this assay is due to the amount of microbial ATP in the food sample.
It is used as a rapid screening test for heavily contaminated foods.
It is used for calculation of the energetic/caloric value of foodstuffs.

15. Spectrophotometric Methods of Food Analysis:

The time needed for the analysis is not an important parameter, since the substrates in food samples are analysed by determination of the enzyme activity.
The total time needed for the analysis is dependent on the amount of the enzyme-substrate present in the sample, since the enzymatic reaction must reach the end-point.
They are always dependent on the change of absorbance of light emitted at 340 nm, because this is the wavelength of maximum absorption of the enzyme co-factors NADH and NADPH, used in all the spectrophotometric food analysis.
A limitation of this type of analysis is that it can only be used to determine the concentration of organic components in a sample.

16. Enzymes as Food Additives:

Enzymes from plants and animals, which are usually consumed by man, are exempted of toxicological testing and accepted as food additives.
Enzymes from microbial sources can not ever be added to foodstuffs, although they are allowed as feed components.
Enzyme products from microbial sources can be added to food and feed if the production process can guarantee there are no viable microorganisms in the final product.
Enzyme products from microbial sources, after being approved by the FDA (Food and Drug Administration) are accepted world-wide as food additives, since they have already been thoroughly toxicologically tested and their production process was verified to follow all the "good manufacturing practices".

17. Immobilized Biocatalysts:

An immobilized enzyme is an enzyme that is always chemically linked to a solid support, the carrier.
Enzymes linked to solid supports are obtained always through covalent binding choosing those functional groups in the protein molecule suitable for chemical reaction under mild conditions.
The linking of enzymes to a carrier through an ionic-binding method always results in the leakage of the enzyme by changes of pH and/or ionic strength during the biocatalysis.
An immobilized enzyme may remain soluble in the catalytic environment, through confinement in semipermeable compartments.

18. Pectinase:

Is an enzyme product with polygalacturonase activity, i.e., it hydrolysis the polygalacturonic acid chain of pectic substances.
Is an enzyme product with pectin esterase activity capable of de-esterification of the polygalacturonic acid chain of pectic substances, allowing the production of low metoxyl polygalacturonic chains.
Is a pure enzyme with both of the previously described activities – the pectin esterase and the polygalacturonase activities.
Is an enzyme blend with pectin esterase and polygalacturonase activities.

19. Proteases are used in the chill proofing of beers:
This sentence means that the proteases are added in the manufacturing process of beer with the purpose of

Degrading the natural polysaccharides of malt to increase the concentration of readily metabolized sugars at much lower temperatures.
Increasing the amino-acid content and nutritional value of beers.
Prevent precipitation of proteins, due to its interaction with polyphenols from malt, at low temperatures (4-7ºC).
Improve the release of aroma compounds in beer at chilling temperatures.

20. Enzymatic Processes can successfully replace well-known and established chemical processes in the food industry, because:

Even if the enzyme product is expensive, its subsequent reuse favours the economy of the process.
Develop under mild conditions of temperature, pH and pressure, which are always better for the safety of the industrial plant and quality of the products, also decreasing the operating costs.
Due to the high specificity for the substrate, they produce fewer by-products, giving rise to a better (tailor-made) food product.
None of the previous answers alone justifies the choice of enzyme processes.

21. Odour threshold:

Odour threshold is any concentration of a compound which permits its detection.
Threshold concentrations for aroma compounds depend on their vapour pressure.
The performance of the sensory panel does not influence the odour threshold.
Temperature does not influence the odour threshold.

22. Constituints of a flavour:

By definition, essences or essential oils are all the compounds obtained by hydrodistillation, steam distillation, expression or solvent extraction of the start material, usually plants or parts of plants (roots, stems, leaves or flowers).
The development of different plant chemotypes are not dependent on the place were the plant is growing.
Natural flavours are mostly metabolites so that their formation in living tissues is complex and dependent on genetic factors being highly influenced by the vegetative cycle and the environmental conditions during the natural growth cycle.
Flavours produced by processing may be direct breakdown products or complex interaction products, but they are not dependent on the processing conditions imposed.

23. Fruit flavours:

The carbohydrates present in fruits are of considerable importance for their quality and edibility.
Lactic acid is one of the acids presents in the volatile fractions of fruits.
The astringency characteristic of fruits does not depend on the presence of phenols.
The flavour components of table fruits are present at higher concentrations than in the aromatic spicy fruits.

24. The aroma compounds of dairy products:

Acetaldehyde is a metabolite that is not important for the dairy products.
The free fatty acids appear to be not important as precursors of flavour compounds such as methyl ketones, essential for blue cheese characteristics or as precursors of compounds arising from oxidation, which may have a negative or positive effect.
Lactic acid is of special importance, for the acidity it creates in the various cultured products and also because the pH drop, which follows lactic acid production, determines the basic structure, characteristic of each cheese variety.
The kind of grapes used does not contribute for the variety flavour of the wine flavour.

25. Flavour and degradation of lipid foods:

Fats and oils are susceptible to oxidation, which produces undesirable volatile compounds and cause detrimental flavour effects to food.
Light, trace metals and temperature do not influence the oxidation of fats and oils.
Antioxidants are widely used in food and cosmetic industries, but they do not prevent oxidation of fats and oils.
Many herbs and spices possess antioxidants, but none of them, not even rosemary extracts, have industrial application.

26. Natural flavouring materials:

Resinoids are prepared by taking up concretes in ethanol.
Absolutes are prepared by extracting plant exudes with solvents such as methanol, ethanol, or toluene.
Absolutes mainly consist of non-volatile, resinous compounds and are primarily used for their excellent fixative properties.
Concretes are not completely soluble in alcohol and, thus, find limited use as perfume ingredients. However they can be employed in the scenting of soaps.

27. Colorants:

Natural colorants as a rule are cheaper than artificial colorants, more stable, and possess a very high tinctorial power.
Recently, the number of dyes suitable for food use has been drastically reduced as a result of toxicological studies and, in Europe, by harmonisation of European Community legislation.
Colorant is generally added to food at the end stage in processing.
Colouring fresh food is more and more used in industry.

28. Extraction methods:

In steam distillation and in Clevenger distillation the material to be extracted is immersed in water, which is then boiled.
In solvent extraction the choice of the solvent may determine the success of the extraction.
Liquid CO2 has no advantages over most conventional organic solvents.
Supercritical extraction normally is not used to obtain extracts from plants.

29. Quality:

Quality control of fragrance and flavour substances, as well as the products derived from them, comprises the comparison of sensory, analytical, and if necessary, microbiological data with standards and specifications.
Quality is an absolute concept.
Determinations of content by chemical parameters, such as esters and carbonyl numbers, are being increasingly supplemented by spectroscopic techniques, such as GC and HPLC.
To obtain data on the sensorial analysis, results from two or three individual from the panel test are enough.

30. Encapsulation:

Normally the spray drying technique is not used for encapsulation.
Encapsulation is a technique that is applied to preserve and/or protect numerous ingredients.
Sodium chloride is added to nutritional dry mixes to fortify a variety of foods including breakfast cereals, dairy products, infantile formulas, and pet foods.
Vitamins, encapsulated with a variety of coatings, including partially hydrogenated vegetable oil, is used in formulations to control colour degradation, rancidity, water absorption, and yeast growth.