Lipid Oxidation, Volatiles and Color Changes of Irradiated Pork Patties Affected by Antioxidants

Changes were measured in TBARS, color, and volatiles of irradiated (4.5 kGy) pork patties with antioxidants (sesamol, quercetin, rutin, BHT, and rosemary oleoresin) during 7 days storage at 4°C. Irradiation accelerated lipid oxidation of raw pork during storage. However, irradiation before cooking did not influence lipid oxidation of cooked pork during storage. Sesamol, quercetin, and BHT were effective in both irradiated raw and cooked pork during 7-days storage. Rosemary oleoresin and rutin were effective only in irradiated raw pork for 3 days. Hexanal, propanal and higher boiling components were well correlated (P < 0.01) with TBARS in cooked pork. Generation of volatiles was reduced by sesamol and quercetin, but the effects of antioxidants on color changes of raw pork patties were minor and inconsistent.     

Variations in Internal Color of Cooked Beef Patties

Seventeen commercially prepared patty formulations were cooked to internal temperature 71°C. Pink cooked color occurred in eight of the products and was due to incomplete denaturation of myoglobin. Although there was some relation between pH and cooked color, other factors seemed to be involved. When products were re-analyzed after 1 yr storage at -27°C, sixteen products were red/pink when cooked to 71°C. This increase in redness after frozen storage could not be explained. Cooking to internal temperatures between 81 and 87°C was necessary for complete disappearance of red/pink color. Premature browning, where a product looks well-done at temperatures lower than 71°C, occurred in one formulation.     

Postharvest Quality and Microbial Population of Head Lettuce as Affected by Moisture at Harvest

Iceberg lettuce was evaluated for yield, microbial population, and postharvest quality either following different irrigation termination (IT) schedules or before and after a rainfall event. Lettuce receiving late (4 d before harvest) IT showed increased weight and diameter, higher aerobic bacteria counts, and lower quality than plants subjected to early (16 d before harvest) IT. Middle (8 d before harvest) IT produced similar yields, and lower microbial population in lettuce than late IT. After rain, microbial population increased by 1.5 and 3.0 log colony‐forming units (CFU)/g in outer and head leaves respectively. The results revealed the importance of managing moisture conditions at harvest to enhance overall quality of lettuce.     

Collagen Contents of Chicken Gizzard and Breast Meat Tissues as Affected by Cooking Methods

The changes in collagen contents of chicken gizzard and breast meat during boiling water and pressure cooking were investigated. The loss of collagen in both tissues increased as the cooking time or temperature increased. The percent of collagen in acid- and salt-soluble forms in gizzard was lower than that of the breast meat. The acid- and salt-soluble collagen from water cooked gizzard were lower than those of the pressure cooked gizzard. Cooking gizzard in boiling water containing 0.5% acetic acid or papain significantly (p<0.05) reduced the collagen content of the tissue.     

Endpoint Temperature, Internal Cooked Color, and Expressible Juice Color Relationships in Ground Beef Patties

Ground beef patties from A- and E-maturity carcasses and imported trimmings were cooked to 55 to 77°C. Internal patty color became less red as endpoint temperature increased. However, some patties cooked to lower temperatures turned brown prematurely. Visual evaluation of internal patty color was not an accurate indicator of patty doneness. Raw material source had little effect on internal patty color. Expressible juices from imported trimmings were less red than those from A-and E-maturity carcasses. Expressible juice became less red and more yellow with increasing endpoint temperature; however, expressible juice never “ran clear.” A more appropriate guideline would be “cook until juices lack redness.”     

Moisture Retention and Textural Properties of Ground Chicken Meat as Affected by Sodium Tripolyphosphate, Ionic Strength and pH

Batches of ground chicken meat were mixed with 10% solutions containing 0.0–5.0% sodium tripolyphosphate and sufficient NaCl to adjust the ionic strength (IS) of the solutions from <0.7 to 6.0 at pH 6.5 to 9.5 in a 6 × 4 × 7 factorial experimental design. Patties prepared from the mixtures were evaluated for pH, cooking loss, and objective texture characteristics. Most effects of STPP were attributable to the direct effect of STPP on IS. However the ability of the phosphate to alter textural properties was greater at a pH value near the pK_a of the phosphate.     

Effect of Frozen Storage Conditions on Yields, Shear Strength and Color of Ground Beef Patties

One-quarter pound (113g) ground beef patties containing 15 or 30% fat were packaged in either polyethylene bags or vacuum-packaged and stored at -12.2°, -23.3°, or -34.4°C for 20 weeks. At 4-wk intervals, samples were thawed and analyzed. The results were compared with fresh samples. Drip loss, cooking loss and shear strength increased with increasing time in frozen storage. Package type affected drip loss and cooking loss but not shear strength. Products with higher f at contents had higher drip loss, cooking loss, shear strength, and color (L, a, and b) values.     

Emulsion Stability and Water Uptake Ability of Chicken Breast Muscle Proteins as Affected by Microbial Transglutaminase

ABSTRACT: Using response surface methodology, the effect of microbial transglutaminase (TG) concentration and incubation time (IT) after emulsification, but before creaming, on the functional properties of chicken meat proteins was examined. TG improved the stability of emulsions (ES) made with a high-salt chicken meat protein extract, although TG did not significantly affect the amount of protein incorporated into the emulsion cream layer. IT significantly enhanced ES when incubated at 40 °C, but not at 4 °C. TG increased the water uptake ability (WUA) of both chicken muscle and chicken muscle protein extract incubated at 40 °C and 4 °C. Similarly, TG increased the protein and water content of the pellet formed in the WUA test. TG therefore appears to be a useful method to enhance the stability and yield of meat batters.     

Oil Uptake in Deep Fat Frying as Affected by Porosity

The porosity of a restructured potato product ranged from 0.089 to 0.168 after fluctuating subfreezing storage temperatures. A linear relation was found between oil uptake during frying and porosity prior to frying. Bulk and particle density, and porosity were monitored for up to 5 min during deep-fat frying. Particle density increased gradually, bulk density decreased and porosity increased noticeably. After an initial short period, oil uptake correlated linearly with porosity of the fried product. A new term, “net porosity” which excluded the void volume occupied by oil was developed for describing the oil uptake mechanism.     

Color Changes of Chicken Leg Patties Due to End-point Temperature, Packaging and Refrigerated Storage

Patties of broiler leg muscle were heated to end-point temperatures (EPT) of 60, 65, 70, 75, 80 or 85°C, packaged in polyethylene bags or vacuum skin packs and stored at 4°C for up to 14 days. As EPT increased, lightness (“L”) and yellowness (“b”) increased whereas redness (“a”) decreased. Patty top surface center color “L” and “a” values correlated highly with the interior cut surface values. Patties stored in plastic zipper bags tended to show a lower “b” (P<0.05) reading than patties stored in vacuum skin packs and plastic film. Storage for 2 wk at 4°C increased “L”, and decreased “a” and “b” for all patties. As EPT increased, the color difference (AE) at the interior cut surface of patties heated to lower EPT and those heated to 85°C were reduced.     

油炸温度-时间对鸡肉中丙烯酰胺含量的影响

本文研究了油炸温度-时间对鸡肉表面和中心丙烯酰胺含量的影响。分别测定了在160℃、170℃和180℃油炸过程中鸡肉内外温度变化。油炸18min后,中心温度没有超过115℃,而表面温度升高很快。结果显示,鸡肉表面和中心丙烯酰胺含量差别很大,在160℃、170℃和180℃油炸18min后,表面丙烯酰胺含量分别为3.03μg/g、6.62μg/g和8.59μg/g;而中心丙烯酰胺含量在180℃只有2.26μg/g。虽然在160℃下油炸18min,表面温度没有超过130℃,但在此温度下也能产生丙烯酰胺,说明在低于130℃下也能产生丙烯酰胺。     

Color Stability and Microbial Growth Relationships in Beef as Affected by Endogenous α-Tocopherol

Longissimus muscle from Holstein steers supplemented with vitamin E at 500 or 2000 mg/head/day showed less surface metmyoglobin accumulation than controls during 12 days storage at 4°C. Temperature abuse at 25°C for 24 hr increased metmyoglobin formation; vitamin E supplementation diminished the adverse effect of temperature abuse. No differences (P > 0.05) in bacterial load were observed among the 3 vitamin E treatments during storage. Sensory panelists preferred vitamin E-supplemented beef steaks in visual acceptance. Panelist assessment of discoloration correlated highly with a value and hue angle. In general, elevated α-tocopherol concentrations in beef steaks did not affect panelist assessment of meat spoilage.     

Flavor and Oxidative Stability of Ground Beef Patties as Affected by Source and Storage

Chuck muscles and fat from silage plus grain- and forage-fed steers were stored 7 days at 4°C before patty manufacture or processed into patties and stored at 4°C or ?32°C. The thiobarbituric acid values were constant from 0 to 4 days for frozen patties but decreased (P<0.05) for refrigerated patties. Evaluated by an 11-member trained sensory panel, frozen patties had lower (P<0.05) rancid flavor intensity than refrigerated patties; rancid flavor increased from 0 to 2 or 4 days storage in refrigerated patties. Frozen patties from silage plus grain-fed steers had higher (P<0.05) beefy flavor intensity scores than those from forage beef. However, diet source had no effect (P>0.05) on refrigerated patties.     

Microwave Cooking Properties of Ground Pork Patties as Affected by Various Fat Levels

ABSTRACT: Ground pork patties were processed from pork hams to achieve fat levels of 5%, 10%, 15%, 20%, and 25%. Each patty was cooked in a microwave oven to 75 °C from a thawed state. As fat levels increased, cooking time decreased. Total cooking loss and drip loss were highest for 25% fat patties and lowest for 5% fat patties. High-fat patties (20% and 25%) had greater reductions in dia than did 5% to 15% fat patties, but had less change in patty thickness. Shear force values decreased as fat levels increased. Visual evaluations also indicated a greater presence of air pockets in high-fat patties. In raw patties, low-fat samples were darker (had lower L * values) and were redder (had higher a * values) than patties with more fat. However, these differences were relatively smaller when the patties were cooked. As fat levels increased, flavor, tenderness, juiciness, and oiliness ratings increased. These differences were not as apparent when comparing among low-fat patties or high-fat patties. Keyword: microwave, cooking, fat, pork patty     

Lipid Oxidation in Ground Beef Patties as Affected by Time-Temperature and Product Packaging Parameters

Oxidative rancidity in fresh and stored ground beef samples was measured using a thiobarbituric acid (TBA) assay with antioxidant protection. The independent variables were fat concentration (15 or 30%), package type (polyethylene or vacuum-packaged), freezer storage temperature (-12.2°, -23.3° or -34.4°C) and storage time (4, 8, 12, 16, or 20 weeks). At the end of each storage time samples were thawed and TBA values were determined on the samples before and after cooking. TBA values increased during the first 12 to 16 weeks after which time it decreased for both the cooked and uncooked samples. The higher fat samples, packaged in polyethylene, had higher TBA values for both cooked and uncooked patties. Uncooked patties stored at - 12.2°C had higher TBA values than those stored at -23.3°C or -34.4°C but cooked sample TBA values showed no dependence on storage temperature.     

Precooked Reduced-Fat Beef Patties Chemical and Sensory Quality as Affected by Sodium Ascorbate, Lactate and Phosphate

Beef-carrageenan (BC; 10% fat) patties—with sodium ascorbate (0.05%), sodium lactate (3%), sodium tripolyphosphate (0.3%), ascorbate-phos-phate, ascorbate-lactate, or none—and 20%-fat all-beef patties were cooked, aerobically or vacuum packaged, and stored at 4°C or ?20°C. Fat level had a greater effect on texture than did additives. Lactate and phosphate increased cooking yield of BC patties. Phosphate was antioxidative but not antimicrobial. Ascorbate was antioxidative and reduced aerobic plate counts (APCs) of aerobically packaged refrigerated BC. Lactate reduced APCs of both aerobically and vacuum packaged BC patties. Lactate had a prooxidative effect in aerobically-packaged/frozen patties but showed no such effect in vacuum-packaged/frozen patties or refrigerated patties. Ascorbate-phosphate was most effective in minimizing flavor deterioration in refrigerated BC patties.     

Selenium Content of Chicken Meat as Affected by Cooking

Twelve dressed chickens of the same flock were quartered and prepared by four cooking treatments: microwaving, conventional oven cooking, broiling, and panfrying. The mean value of selenium (fluorometic method) in raw chicken was 0.38 μg/g dry weight, with no significant differences between white and dark meat. There was insignificant loss of selenium due to cooking. Cooked chicken breast had a significantly higher level of dialysable selenium compounds (MW < 2000 daltons) than raw chicken.     

Composition and Stability of Goat Meat Patties as Affected by Breed Type and Feeding Regimen

Ground meat patties were made using knife-separable lean (frozen-thawed) composites from meat-type (Spanish, Spanish Boer) goats assigned to two feeding regimens (feedlot or range) and fiber-type (Angora, Spanish Angora) goats assigned to the feedlot regimen. Weight losses from pan-frying (mainly moisture loss) were 17.7 to 21.6%. Range meat-type goat samples had a higher proportion of total saturated fatty acids than the feedlot counterparts. After refrigerated storage, raw or cooked patties (aerobically packaged) from the range goats had lower TBA values than those from the feedlot goats. At – 20°C, all samples, raw or cooked, exhibited low TBA values throughout 120 days of storage.     

油炸食品类型对煎炸油废弃指标变化规律的影响

为明确油炸食品类型对煎炸油废弃指标的影响,选择馓子、牛肉丸、加沙分别代表淀粉基、蛋白质基和混合基食品,以大豆油、棉籽油为煎炸油,研究不同油炸温度条件下不同类型油炸食品对煎炸油酸价（acid value,AV）、总极性组分（total polar compounds,TPC）及废弃点的影响。结果表明,不同食品油炸过程中煎炸油AV、TPC 均逐渐上升;油炸食品类型对大豆油和棉籽油的AV、TPC 和废弃点均具有显著影响;大豆油油炸过程中,牛肉丸、馓子、加沙分别在160、170、180 ℃条件下劣变速度最快,废弃点分别为40～48、48～56 h 和48～56 h;棉籽油油炸过程中,牛肉丸、馓子、加沙分别在170、180、170 ℃条件下劣变速度最快,废弃点分别为48～56、48～56 h 和48～56 h。不同条件油炸过程中油脂AV 和TPC 均呈正相关。     

Gelling Temperatures of Gellan Solutions as Affected by Citrate Buffers

Effects of citrate buffers at pH 3.5 and 5.0 on gelling temperatures of gellan solutions with 0.4–1.8% gellan and 1.5–60 mM Ca²⁺were studied. Partial dissociation of the carboxyl groups in gellan polymer in pH 3.5 solutions resulted in weakened gels. The pH 3.5 buffer exhibited weak chelating ability for Ca²⁺. The gelling temperature of gellan solutions at pH 3.5 was quantitatively related to polymer and cation concentrations using a similar model to that for gellan water solutions. The pH 5.0 buffer exhibited strong chelating ability. Gelling temperatures at pH 5.0 were generally lower than those at pH 3.5, except at low calcium concentrations.