Fat in dry matter

Figure 11.10. Effect of homogenization pressure on the hardness (A, B) and springiness (C, D) of 1 week (a, c) and 6 week (b, d) -old Mozzarella cheeses with different levels of fat-in-dry matter (low-fat, LF, 22%, w/w high-fat, HF, 49%, w/w) and manufactured using a low (FT, 32°C) or high (HT, 45.9°C) curd scalding temperature FFHT ( ), FFFT (O), HFHT (A), or HFFT (A) (drawn from data of Tunick et al., 1993b).

The quality of cheese is influenced by its composition, especially moisture content, NaCl concentration (preferably expressed as S/M), pH, moisture in nonfat substances (MNFS essentially ratio of protein moisture) and % fat in dry matter (FDM). At least five studies (O Connor, 1971 Gilles and Lawrence, 1973 Fox, 1975 Pearce and Gilles, 1979 Lelievre and Gilles, 1982) have attempted to relate the quality of Cheddar cheese to its composition. While these authors agree that moisture content, %S/M and pH are the key determinants of cheese quality, they disagree as to the relative importance of these parameters. 

Gouda cheese with 40% fat in dry matter. Edam cheese with 48% fat in dry matter. 

The synthesis of microbial fat by bacteria is often ignored because the average fat concentration in dry biomass does not exceed 10%. However, there are strains of Arthrobacter sp., Mycobacterium, and Corynebacterium that are able to accumulate from 30 to 80% lipids in dry matter. Unfortunately, there are other problems related to low growth rates and yields of bacteria, lipid extraction, and the possible allergeiucity and toxicity of the resulting lipids. Microalgae (e.g., Botryococcus braunii and Chlorella pyrenoidosa) serve as attractive sources of PEFA. Dry biomass fat can amount to as much as 85% (Kay, 1991). Moreover, microalgae are a very... 

The method described can be used only in samples with a high content of fat. Total lipids should be present as over 10% in dry matter. The accuracy depends also on the fatty acid composition. Lipids with a characteristic main component will also show one main cyclobutanone. In the case of an equal distribution of different fatty acids the concentration of derived cyclobuta-nones will be low. In most cases DCB, TCB and TECB are useful indicator substances for identifying irradiated foods. 

The oil content of oats is higher than that of most of the other cereal grains, and about 60 per cent of it is present in the endosperm. As mentioned earher, the oil is rich in unsaturated fatty acids and has a softening effect on the body fat.The range in dry matter composition of 171 samples of oat grain harvested in Wales is shown in Table 22.2. 

Kim and Keeny [55] detected between 43,270 and 21,890-mg kg epicatechin in eight different cacao genotypes Tomas-Barberm et al. [56] quantified 25,650-mg kg fat-free dry matter Gotti et al. [57] reported on 15,300-5,700 mg kg It is still unclear whether environmental or genotypic factors dominate the variation. The diastereoisomer (+) catechin is lower in mature cocoa seeds 646 mg kg [56], 450-140 mg kg [57]. 

Development of the reserves in fat-storing seeds has been approached experimentally from two main standpoints (1) to elucidate the pathway of fatty acid biosynthesis and (2) to measure the accumulation of fat and dry matter and analyze it for fatty acid content. 

The fat content of lupine is relatively small, except for the South American species L. mutabilis, which contains about 22-24% of oil in dry matter). In the technological production of oil from this lupine, about 60% of alkaloids present in bitter varieties are removed during extraction with hexane. Subsequent refining decreases their concentration in the oil down to 0.0005%. Meals are debittered by extraction with ethanol containing hydrochloric acid, which decreases the alkaloid content from the original amount of 3.2% to 0.1-0.2%. 

Triglycerides, lecithin, and ergosterol are the main constituents of yeast lipid (feu. Oleic and palmitic acids predominate in yeast fet. These resemble the composition of common vegetable fats. Ergosterol. the precursor of calciferol (vitamin D2) varies from 1 to 3% of yeast dry matter. 

The components are usually calculated on a normal percentage of moisture (18% for unstuffed leathers see later). In some cases the results have to be calculated on the dry matter and for stuffed leather sometimes on the dry fat-free material. 

In fatty fish, the total lipid content correlates negatively with the content of dry matter and water. The fat-water line has been recognized in dozens of species of fish (Kizevetter, 1942 Levanidov, 1950 Luhmann, 1953, 1955 Brandes and Dietrich, 1958 Krivobok and Tarkovskaya, 1960 Shulman, 1961). The correlation is a good one (r=-0.8 to -0.9), but each species has its own equation. In Black Sea sprat, for example, the relationship is Y=-13.28 + 0.84X, where Y is the total lipid content and X the content of dry matter... 

Oleic acid was increased to 48% of total milk fatty acids by feeding oleamide as a rumen-protected source of oleic acid (Jenkins, 1998). The response was nearly linear up to 5% of supplement in the diet dry matter. Proportions of all de uovo-synthesized milk fatty acids, except butyric, were reduced (Jenkins, 1999). LaCount et al. (1994) abomasally infused fatty acids from canola or high oleic acid sunflower oil into lactating cows. The transfer of oleic acid to milk fat was linear (slope = 0.541 0 350 g infused/ day) the proportion of oleic acid in milk fat increased and proportions of all de novo-synthesized fatty acids, except C4 and C6 decreased. The proportion of Ci8 o also was unchanged. Linoleic acid from canola also was transferred linearly (slope = 0.527 0-90 g infused/day). These transfers from the intestine are nearly identical to that reported by Banks et al. (1976). Hagemeister et al. (1991) reported 42 to 57% transfer of abomasally-infused linolenic acid to milk fat. 

Relationships between trans-10, cz.y-12 CLA and milk fat synthesis have been examined. There is a curvilinear relationship between the reduction in milk fat yield and the abomasal infusion dose of trans-10, cis-12 CLA (Figure 3.4). Trans-10, cis-12 CLA is a very potent inhibitor of milk fat synthesis in dairy cows a dose of 2.0 g/d (<0.01% of dry matter intake) reduced milk fat synthesis by 20%. Trans-10, cis-12 CLA is also incorporated into milk fat and in this case the relationship is linear (Figure 3.4) a summary of seven studies showed that the transfer efficiency of aboma-sally-infused trans-10, cis-12 CLA into milk fat averaged 22% (de Veth et al., 2004). The linear relationship in transfer to milk fat is remarkable when one considers that the yield of milk fat is simultaneously decreased as the abomasal dose of trans-10, cis-12 CLA is increased. This suggests that the mechanisms which coordinate the CLA-induced decrease in the use of preformed fatty acids for milk fat synthesis have a less pronounced effect on the mammary uptake and incorporation of trans-10, cis-12 CLA into milk fat, but the basis for this difference is unknown. 

The major organic component in hone is collagen, which constitutes some 90 to 96% of the dry fat-free organic matter Collagen is a long fibrous protein, two-thirds of which is formed of only four amino acids Collagen is about 33% glycine, 11% alanine, and 22% proline and hydroxyproline (13) ... 

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