Food Biochemistry and Food Processing (2 edition)

BLBS102-c16 BLBS102-Simpson March 21, 2012 10:54 Trim: 276mm X 219mm Printer Name: Yet to Come

312 Part 3: Meat, Poultry and Seafoods

Table 16.3.Physical Factors Affecting Lipolytic Activity During Meat and Meat Products Processing

Factor Typical Trend Effect on Lipolytic Enzymes

pH Near neutral pH in dry-cured ham

and cooked meat products.

Favors the activity of neutral lipase, neutral esterase and

hormone-sensitive lipase.

Slightly acid in aged meat Favors the activity of lysosomal acid lipase, acid esterase and acid

phospholipase

Acid pH in dry-fermented sausages Favors the activity of lysosomal acid lipase, acid esterase and acid

phospholipase

Time Short in aged meat, cooked meat

products and fermented products

Short action for enough enzyme action but significant oxidation of

the released fatty acids

Medium in dry-fermented sausages

and long in dry-cured ham

Time allows significant biochemical changes in dry sausages and

very important in dry-cured ham

Temperature High increase in cooking and

smoking

Enzymes are strongly activated by cooking temperatures although

for short time

Mild temperatures in fermentation

and dry-curing

Enzymes have time enough for its activity even though the use of

mild temperatures. Lipases are active even during freezing

storage of the raw meats

Water activity Slightly reduced in cooked meats Enzymes have very good conditions for activity

Substantially reduced in dry-meats. Muscle neutral lipase and esterases are affected. Rest of lipolytic

enzymes remain unaffected byawdrop

Redox

potential

Anaerobic values in postmortem

meat.

Slight effect on lysosomal acid lipase and phospholipase. More

intense for rest of lipases

Staphylococcus saprophyticus;S. carnosusandStaphylococcus

xylosuspresent poor and variable lipolytic activity (Montel et al.

1993). Lactic acid bacteria have poor lipolytic activity, mostly

intracellular. Many molds and yeasts such asCandida,Debary-

omyces,Cryptococcus,andTrichosporumhave been isolated

from fermented sausages, and all of them exhibit lipolytic ac-

tivity (Ordonez et al. 1999, Ludemann et al. 2004, Sunesen and ̃

Stahnke 2004).

The increases in the levels of free fatty acids show a great

variability depending on the raw materials, type of sausage, and

processing conditions (Toldra et al. 2002). The increase may ́

reach 2.5–5% of the total fatty acids, and the rate of release

decreases in the following order: oleic>palmitic>stearic>

linoleic (Demeyer et al. 2000). The release of polyunsaturated

fatty acids from phospholipids is more pronounced during ripen-

ing (Navarro et al. 1997). Some short-chain fatty acids such as

acetic acid may increase, especially during early stages of ripen-

ing. The generation of volatile compounds with impact on the

aroma of fermented sausages depends on the type of processing

and the starter culture added (Talon et al. 2002, Tjener et al.

2004). Some of the most important are aliphatic saturated and

unsaturated aldehydes, ketones, methyl-branched aldehydes and

acids, free short-chain fatty acids, sulfur compounds, some alco-

hols, terpenes (from spices), and some nitrogen-derived volatile

compounds (Stahnke 2002).

Lipolysis in Dry-Cured Ham

The generation of free fatty acids in the muscle is correlated

with the period of maximal phospholipid degradation (Motilva

Table 16.4.Chemical Factors Affecting Lipolytic Activity During Meat and Meat Products Processing

Factor Typical Trend Effect on Lipolytic Enzymes

NaCl Low in aged meat No effect on enzyme activity

Medium concentration in cooked meat products Partial inhibition of muscle neutral lipase and

esterases. Adipose tissue lipases not affected.

Activation of lysosomal acid lipase and acid

phospholipase

High concentration in dry-cured hams Slight activation of lysosomal acid lipase and

acid phospholipase

Nitrate and nitrite Concentration around 125 ppm in cured meat products No significant effect

Ascorbic acid Concentration around 500 ppm in cured meat products Slight inhibition of all lipolytic enzymes

Glucose Poor concentration in aged meat and dry-cured ham No effect

High concentration (up to 2 gL-1) in fermented meats No effect