PERFORMANCE CHARACTERISTICS AND FATTY ACID COMPOSITION OF PIGS FED A DIET WITH DOCOSAHEXAENOIC ACID

Market hogs were fed a ration from 22–42 days prior that contained the omega-3 fatty acid docosahexaenoic acid (DHA) supplemented at 0, 0.125 and 0.250 kg/pig in the form of the microalgae , Schizochythrum sp. There were no differences (P>0.05) between the average daily gain, feed consumption, or feed efficiency of the controls and those that received a DHA supplementation. Of the 21 fatty acids analyzed, the concentration of only five were affected by DHA supplementation. Muscles from the ham, loin, and shoulder of pigs that received 0.250 kg of DHA contained more eicosapentaenoate, docosahexaenoate, and docosapentaenoate n-6 and n-3 than either the controls or those that received 0.125 kg. Supplementation of DHA in the ration at 0.125 kg caused an elevation of docosapentaenoate n-6 and docosahexaenoate. These data suggest that addition of DHA to the diet can elevate the amount of this omega-3 fatty acid in pork with potential health benefits to consumers.     

EFFECTS OF DOCOSAHEXAENOIC ACID POSITIONAL DISTRIBUTION ON THE OXIDATIVE STABILITY OF MODEL TRIACYLGLYCEROL IN WATER EMULSION

The effect of the positional distribution of docosahexaenoic acid (DHA) within triacylglycerol (TAG) molecules on the oxidative stability of oil-in-water emulsions was investigated by using a synthetic TAG regio-isomer pair SDS (1,3-dioctadecanoyl-2-[4,7,10,13,16,19-docosahexaenoyl] glycerol) and SSD (1,2–dioctadecanoyl-3-[4,7,10,13,16,19-docosahexaenoyl] glycerol), where S and D represent stearic acid and DHA, respectively. Oil-in-water emulsions (10%, w/w) of each isomer were subjected to accelerated autoxidation by continuous exposure to air at 50C in the absence of light. Oxidation during the exposure (storage) was monitored by measuring a series of volatile compounds characteristic of DHA oxidation. SSD emulsion oxidized faster than SDS emulsion, showing that DHA is more stable to oxidation when located at the sn -2 position of the TAG compared with the sn -1(3) position. This regio-isomeric effect is similar to that previously reported for bulk oil oxidation.

PRACTICAL APPLICATIONS

Many of the food products that have been selected for fortification with omega-3 oils such as milk, yoghurt, salad dressings and juices are oil-in-water emulsions. This study, for the first time, demonstrated that the regio-isomeric effects on oxidative stability of docosahexaenoic acid observed for bulk oil also apply to oil-in-water emulsion. Thus, potential exists for enhancing the oxidative stability of omega-3-fortified emulsion foods through modification of triacylglycerol structure.     

EFFECT OF ULTIMATE pH ON THE QUALITY CHARACTERISTICS OF PORK

A study was conducted to characterize the relationship between Longissimus thoracis ultimate pH(LTpH) and pork quality. Animals (n = 47) were selected based on LTpH measured at 24 h postmortem. Data were analyzed using regression procedures with ultimate pH as the independent variable, and relationships were determined to be linear (L), quadratic (Ql or cubic (C). Ultimate pH explained 79% (C) of the variation in subjective color, which increased as pH increased. Drip loss, purge loss and L* value decreased as LTpH increased (R²= 0.57C, 0.77 Q and 0.68 Q, respectively). Shear force decreased and sensory juiciness increased as LTpH increased (R²= 0.26Q and 0.46C, respectively). However, of flavor intensity increased as LTpH fell below pH 5.2 or exceeded 6.1(R²=0.52C). Increasing LTpH, up to a point, will improve fresh pork quality and processed meat properties, whereas, above approximately 6.1, of-flavor may increase.     

CHARACTERISTICS OF MICROWAVEABLE PORK CHOPS

Blade tenderized whole muscle cuts and restructured chops were conventionally cooked (CO), microwave cooked (MW), and precooked/microwave reheated (CMW) and stored for 2, 15, and 21 days. Blade tenderization did not affect (P > 0.05) these sensory traits evaluated with the exception of texture. Precooked products had higher (P < 0.05) TBA values than conventionally cooked samples for both whole and restructured chops. TBA values increased (P < 0.05) with storage time for up to 21 days. Whole muscle chops that were conventionally cooked had the lowest (P < 0.05) peak force values and the highest (P < 0.05) texture scores. After 21 days of storage of whole muscle samples, overall flavor scores decreased (P < 0.05) and juiciness scores improved (P < 0.05) when compared to samples held for 2 days. Storage time had a minimal relationship to peak force values and no effect on sensory scores of restructured samples.     

FRANKFURTERS SUPPLEMENTED WITH CORN GERM PROTEIN: SENSORY CHARACTERISTICS,PROXIMATE ANALYSIS AND AMINO ACID COMPOSITION1

Defatted corn germ protein (CGP) has been studied as a functional or substitute ingredient of frankfurters. The proximate composition (protein, fat, moisture, ash) and amino acid content of hexane- and supercritical-CO₂-defatted CGP and frankfurters containing CGP were determined. CGP was incorporated in frankfurters as in a powder, slurry form and as a stabilizer of emulsions. Proximate analysis showed significantly lower fat content of CGP processed by a modified procedure and a reduction of fat content in meats containing CGP. Levels of essential amino acids in CGP compared favorably to those in sodium caseinate, hen's egg protein, and soybean protein. Except for isoleucine, CGP meets or exceeds a FAO provisional amino acid pattern recommended for human consumption. No significant differences were found in amino acid composition of hexane- or supercritical-CO₂-defatted CGP. Amino acid composition of frankfurters was not greatly altered by the addition of CGP at the levels studied. An acceptable, weak corny aroma and taste could be detected at 2.4 and 3.5% levels of added CGP. Defatted CGP with its high protein content and amino acid pattern combined with relatively low cost has potential as an extender, fortifier, and binding agent in frankfurters and other comminuted meats.     

SODIUM ACID PYROPHOSPHATE IN LINKED SAUSAGES MADE WITH PORK AND/OR GOAT MEAT

Five combinations of pork and goat were used to formulate linked sausages in reciprocal increments of 25% (e.g., 100% pork, 75% pork/25% goat meat, etc.). Each formulation was made with or without 0.25% sodium acid pyrophosphate (SAPP), stored in a retail case at 3°C and sampled at 0, 3, 6, 9, and 12 days. Sausages made with 25 or 50% goat meat, regardless of SAPP, were not different (P> 0.05) in off flavor from sausages made with 100% pork and SAPP. SAPP decreased pH values, reduced percentages of cooking loss in 4 of 5 comparisons and slightly improved visual color scores for sausages during initial storage periods of 0 and 3 days.     

SUPERIOR OXIDATIVE STABILITY OF DOCOSAHEXAENOIC ACID-ENRICHED OILS IN THE FORM OF PHOSPHOLIPIDS

Oxidative stabilities of docosahexaenoic acid (DHA, 22:6 n-3)-enriched oils (7.0 – 7.1 mol% of total fatty acids), in the form of phospholipids (PL), triacylglycerols (TG) and ethyl esters (EE), were comparatively investigated with those of control oil (palm oil supplemented with 20% soybean oil; containing no DHA). Autoxidation of sample oil (50 mg) was performed in a 10 mL glass vial at 25C for 42 days in the dark. During the oxidation, headspace oxygen absorption was significantly lower in oil in the form of PL than TG and EE, and was almost equivalent to that of control oil. At day 42 of oxidation, peroxide value and carbonyl value of PL were lower than those of TG and EE. The change of constituent fatty acids during the oxidation was larger in TG and EE than PL. The results indicated that DHA-enriched oils in the form of PL are more stable to autoxidation than those in the form of TG and EE.     

PHYSICAL AND MICROBIAL CHARACTERISTICS OF PORK LOINS IN MODIFIED ATMOSPHERE PACKAGES

Bone-in pork loins (n = 45) were selected from a commercial facility, subjected to one of three gas flush packaging treatments: NC: 75% N₂, 25% CO₂; ONC₁: 45% 0₂, 35% N₂, 20% CO₂; ONC₂: 66% O₂, 9% N₂, 25% CO₂, and stored for 7, 14 or 21 days at 0±2C. After storage, treatment and storage effects on visual evaluations, storage characteristics, microbial analysis and retail display characteristics were determined. The ONC¹ and ONC²treated loins had less discoloration after 21 days than NC treated loins, and NC treated chops had the least desirable retail display characteristics (P < 0.05). Fewer (P < 0.05) lactic acid producing bacteria (day 21) were found on NC treated loins, resulting in chops with a shorter retail shelf-life. These results indicate that higher oxygen levels (45 and 66%) are necessary for the modified atmosphere storage of fresh pork loins for 21 days.     

PHYSICAL AND SENSORY CHARACTERISTICS OF PRECOOKED, REHEATED PORK CHOPS WITH ENHANCEMENT SOLUTIONS

Pork loins were pumped to 110% of original weight with solutions containing 0.35% salt and 0.35% phosphate (P), salt and phosphate plus 3% sodium lactate (SL), or salt and phosphate plus 2.5% potassium lactate/potassium acetate (PL/PA). Chops were evaluated freshly cooked and precooked, stored (4C, 2 days) and reheated. Chops from SL and PL/PA chops experienced lower cook losses than unpumped controls. Reheating produced additional cook losses which were unaffected by enhancement treatment. Enhancement produced reheated chops with lower shear values and higher tenderness scores than those of freshly cooked controls, and addition of either SL or PL/PA produced even more dramatic results. Warmed-over flavor after reheating precooked chops was reduced by the SL enhancement solution.     

释酸剂在锦纶织物弱酸性染料染色中的应用

探讨了释酸剂用量、加入方式以及起始pH值等对锦纶弱酸性染料染色的上染速率和上染率的影响，结果表明：释酸剂HTA能逐渐刚氏染液的pH值，在不改变染色牢度的前提下，可提高匀染性。     

QUALITY OF BREAD SUPPLEMENTED WITH SILVER EAR

Silver ear ( Tremella fuciformis Berkeley) was used to substitute wheat flour to make bread. Bread quality including specific volume, color and sensory evaluation, and taste components including proximate composition, soluble sugars, free amino acids and 5'-nucleotides in bread supplemented with silver ear were analyzed and compared with those of white bread. White bread and 5% silver ear bread had a comparable proximate composition. Specific volumes of 2% and 5% silver ear breads and white bread were 4.02, 3.96 and 3.79 cm³/g, respectively. Both breads contained considerately low amounts of monosodium glutamate-like and sweet components of free amino acids and flavor 5'-nucleotides. The white bread looked lighter and whiter than 5% silver ear bread. All sensory results indicated that two breads were moderately acceptable. Overall, silver ear could be incorporated into bread to provide its beneficial health effects.

PRACTICAL APPLICATION

Silver ear mushroom ( Tremella fuciformis Berkeley) is commonly used as food in Oriental countries and is also a traditional Chinese medicine. The mushroom can be added to food as a supplement to extend and broaden its consumption and provide the beneficial health effects through various food products. Bread is consumed all over the world and many food ingredients have been included in bread formulation to increase its diversity, nutritional value and product appeal. Accordingly, the mushroom was used to substitute wheat flour to make bread. Bread quality including specific volume, color and sensory evaluation, and taste components including proximate composition, soluble sugars, free amino acids and 5'-nucleotides in silver ear bread were valuable information for its practical application. The present work showed that silver ear could be incorporated into bread to provide its beneficial health effects.     

EFFECT OF CONSUMING FOOD SUPPLEMENTED WITH SINGLE CELL PROTEIN ON URINE AND SERUM URIC ACID LEVELS

Supplementation of pizzas and date bars with different protein concentrates was found to increase their protein content significantly, but the addition of a yeast protein concentrate (SCP) derived from petroleum via alcohol was found to increase the nucleic acid content of the fortified formulations linearly with the amount of added SCP. The consumption of a total of 30 g of SCP via the fortified food for 3 weeks increased levels of uric acid in serum an average of 8 mg/100 ml and in urine up to 1210 mg/24 h. Two weeks after termination of the yeast intake, both values dropped to near-normal levels.