EFFECT OF COOKING OIL TYPE ON FINAL CHOLESTEROL CONTENT AND FATTY ACID COMPOSITION OF GROUND BEEF

The purpose of this study was to compare three oils for extraction of cholesterol when used to cook ground beef and to determine the effect of oil type on fatty acid composition of the ground beef. Ground beef (30 % fat) was cooked in 1 L of corn, canola or palm oil at 100–110C and then rinsed with 500 ml of boiling water, which significantly decreased ether-extractable fat. Control hamburger was skillet-fried without any added oil. Total lipids were extracted and analyzed for fatty acid composition and cholesterol content. Changes in fatty acid composition of residual fat on the meat after cooking reflected those of the oils used for cooking. Cholesterol was significantly lower in all oil-cooked hamburger than in the control. In conclusion, cooking ground beef in any of the three vegetable oils will extract cholesterol, and the lipid remaining after a boiling water rinse will contain fatty acids characteristic of the cooking oil.     

FACTORS AFFECTING TENSILE AND WARNER-BRATZLER SHEAR VALUES OF RAW AND COOKED MEAT

The influence of slit width on the force deformation curves obtained for raw and cooked meat of different myofibrillar contraction states was investigated with a modified version of the Warner-Bratzler (WB) shear device. Decreasing the clearance or compressing the sample directly onto a base plate (i.e. no slit) had little effect on the initial yield force values. Meat samples retained most of their original tensile strength after compression to initial yield on the shear device. Even cold-shortened cooked samples compressed to peak force values retained over 30% of their original tensile strength. Peak tensile and peak WB shear force measurements were highly correlated: R²= 0.71, 0.94 and 0.88 for raw, stretched/cooked and contracted/cooked samples, respectively. The slopes (WB on tensile) of the regression lines were increased by both cooking and by contraction to below rest length. These results indicate that components other than tensile in the WB shear force measurements were increased by cooking and by myofibrillar contraction.     

FATTY ACID COMPOSITION AND TOCOPHEROL CONTENT OF AMAZONIAN PALM OILS

The characteristics of oils recovered from seeds of Astrocaryum chambira and A. urostachys have been evaluated. The gas chromatographic analyses showed that lauric and myristic acids are predominant fatty acids accounting for 50.8–52.3 and 26.2–28.1% of the total, respectively; thus, resembling closely to palm kernel stearines. Tocotrienols were the major antioxidants present in both Astrocaryum chambira and A. urostachys Kernel oils. Application of these oils in the confectionery industry without use of any fractionation techniques is recommended.     

AMINO ACID, FATTY ACID, CHOLESTEROL AND OTHER STEROLS ANALYSES OF DIFFERENT PIZZA FORMULATIONS

The protein content of many food products may be enriched by the addition of protein concentrates. Textured vegetable protein (TVP) and single cell protein (SCP) were added in varying amounts to a pizza formulation and stored at -20°C until used. The fabricated pizzas were analyzed for amino acids, total fat, fatty acids, sterols, water, protein, ash and cis, cis-methylene interrupted polyunsaturated fatty acids. The addition of TVP and SCP increased the protein content by an average of 18%. Certain amino acids, such as lysine, arginine, leucine and threonine, were significantly increased with the addition of TVP and SCP. The fat values were generally lower in pizzas with TVP and SCP, and the ash content increased. The moisture content ranged from 46 to 49%, except for the “beef + 5% SCP in crust” which was 41%. The fatty acid and sterol profiles were generally very similar.     

COMPARISON OF PHYSICAL METHODS FOR ESTIMATING THE MATURITY OF RAW, FROZEN AND COOKED PEAS

The back extrusion cell, Maturometer, Kramer shear press, FMC Tenderometer, and Ottawa Texture Measuring System wire extrusion cell gave useful estimates of the maturity of raw peas but, two viscosity methods gave unsatisfactory estimates. None of the instruments gave useful estimates of maturity of frozen peas that had been thawed or cooked because blanching conditions and the rate of freezing of the peas affected the readings. The most reliable estimate of raw pea maturity from thawed frozen peas was the alcohol insoluble solids content.     

FATTY ACID COMPOSITION AND CONJUGATED LINOLEIC ACID CONTENT OF COW AND GOAT CHEESES FROM NORTHWEST ARGENTINA

ABSTRACT

In this study, we evaluated chemical characteristics, fatty acid composition and conjugated linoleic acid (CLA) content of cow and goat cheeses from Northwest Argentina. Similar chemical and fatty acid composition were determined in milk and cheese of both species. Palmitic, oleic and myristic acids were the most abundant fatty acids in dairy products. CLA level averaged 0.85 and 0.96 in milk and 0.76 and 1.04 g/100 g of fatty acids in cheese of cow and goat, respectively. Cis‐9,trans‐11 was the major isomer present in both species. Significant differences in CLA desaturase activity were observed, showing a value of 0.068 and 0.064 in milk, and 0.077 and 0.071 in cheese of cow and goats, respectively. Good nutritional properties were determined for cheeses of both species, which are fed on natural pasture during spring and summer seasons. Goat's cheese represents a higher source of CLA for human consumers than cow's cheese, offering from 156.6 to 222.6 mg/ 100 g of sample.

PRACTICAL APPLICATIONS

The present work shows the fatty acid composition and chemical characteristics of two fresh cheeses manufactured with cow and goat milk. Animals were fed on natural pasture during summer and spring seasons. It is known that pasture increases conjugated linoleic acid (CLA) concentration in milk fat, and the content in cheese is directly related to it. The CLA content of dairy products for the human consumers was analyzed, showing goat cheese with high polyunsaturated fatty acid content, including CLA. Cow and goat fresh cheese offer CLA as many ripening products of different countries, as cheddar or hard cheeses. Lipid composition of food is related to many illnesses, but some compounds are beneficial to human health. The main sources of CLA are milk and cheeses, and in Northwest of Argentina, no data are reported about it, where artisanal cheeses are consumed by the population. Therefore, the atherogenicity index was determined as well.     

LIPID CONTENT AND FATTY ACID PROFILES OF SOME LESSER KNOWN NIGERIAN FOODS

The lipid content and fatty acid profiles of seven lesser known protein foods in Nigeria, which include raffia palm and oil palm weevils (Rhynchophorus sp.), shrimps (Palaemonetes sp.), periwinkles (Pachynelania byronesis), snails (Vicapara quadrata), tropical oysters (Thais haemastrama) and crayfish (Palaemonetes varians), were determined. The total lipid content (% fresh weight, FW) ranged between 1.8 ± 0.1 and 9.8 ± 0.1. The range of values for neutral lipids, total phospholipids, and glycolipids (mg/g FW) was 10.1 ± 0.7 to 53.6 ± 1.5, 6.1 ± 1.3 to 30.1 ± 1.5, and 2.5 ± 0.2 to 13.1 ± 0.9, while those of total cholesterol and triacylglycerol content (mg/g neutral lipids) were 1.4 ± 0.1 to 7.1 ± 0.2 and 8.3 ± 1.1 to 47.0 ± 1.5, respectively. Crayfish and palm weevils contained higher amounts of total cholesterol and phospholipids, compared with the rest of the foods. The fatty acid profiles showed variation among the different foods. Palm weevils, periwinkles, snails and tropical oysters were shown to contain substantial amounts of essential fatty acids, especially linolenic acid (C18:3n3).     

YIELD, PROXIMATE COMPOSITION AND MINERAL ELEMENT CONTENT OF THREE CULTIVARS OF RAW AND ROASTED PEANUTS

Yield of kernels, proximate composition (moisture, crude fiber, fat, protein and ash), and content of nine mineral elements–Ca, Mg, P, Na, K, Fe, Cu, Zn and Mn-are reported for three cultivars of peanuts, raw and roasted. Roasting resulted in higher concentrations of all nutrients measured in the peanuts except moisture and sodium, whose contents decreased. Although statistically significant differences in nutrient content were noted among cultivars, these differences were of little practical importance. Data on retentions of proximate components and mineral elements with roasting of peanuts indicate that except for moisture and sodium (which were low) and ash (which was high), retentions were close to 100%.     

EFFECT OF FERMENTATION ON THE FATTY ACID CONTENT AND COMPOSITION OF CASSAVA TUBER MEAL

The effect of fermentation on the fatty acids (FA) content and composition of cassava tuber meal has been investigated. The major FA of the cassava tuber meal (CTM) lipid were oleic and palmitic acids. Other FA found in decreasing order were linoleic, linolenic, palmitoleic, stearic, myristic, pentadecanoic, heptadecanoic and nonadecanoic acids. Fermentation of the CTM resulted in substantial increases in the absolute quantities of the individual FA detected except linolenic acid. However fermentation did not alter the pattern of composition of the FA, but it caused increases in the composition of saturated FA and decreases in certain unsaturated ones. Stearic acid increased in composition by about 92.6% and pentadecanoic by about 50%. A reduction of about 72% of the linolenic acid and 24.2% of the palmitoleic acid composition were obtained in the fermented CTM lipid.