Cooking loss and juiciness of pork in relation to raw meat quality and cooking procedure

The study comprised two experiments with the aim to investigate the influence of raw meat quality and cooking procedure on cooking loss and juiciness of pork. The first experiment determined the cooking loss at 60, 70 and 80 °C centre temperature of 10 raw meat qualities (defined according to ultimate pH, drip loss, breed and rearing conditions) when cooked as steaks on a pan or as a roast in oven at a oven temperature of 90 or 190 °C. The differences in cooking loss between the raw meat qualities and the cooking procedures did decrease as the centre temperature increased and were almost negligble at 80 °C. Low water holding capacity (WHC) and low pH resulted in high cooking loss while no difference in cooking loss was observed between meat having medium or high WHC and pH. In the second experiment four raw meat qualities (standard, Duroc, low pH and heavy carcass weight) chosen from the first experiment to ensure a wide variation in cooking loss, were cooked in oven at 90 or 190 °C oven temperature. Juiciness was assessed three times during the chewing process. The results suggested that juiciness experienced initially in the chewing process depended only on the water content of the meat, whereas juiciness experienced later in the chewing process was determined by a combination of the water and intramuscular fat contents and the saliva production during chewing.     

Thiamin, Riboflavin and Niacin Retention in Cooked Cowpeas as Affected by Kanwa Treatment

Retention of three water soluble B-vitamins in dry cowpeas cooked with a local tenderizer, named “kanwa,” were investigated. Results showed cooking (100°C) in kanwa or sodium bicarbonate decreased levels and retention of vitamins compared to controls cooked in water. Levels of vitamins in kanwa-cooked cowpeas were not significantly different from those in NaHCO₃ cooked samples. Retention in the alkaline cooking processes ranged 15–20% (thiamin), 26–49% (niacin) & 53–64% (riboflavin). Soaking followed by boiling at 100°C or pressure cooking (121°C) increased levels and retention of vitamins.     

Influence of Rapid Cooking Methods on the Survival of Trichinella spiralis in Pork Chops from Experimentally Infected Pigs

Pork chops (1.3, 2.5 or 3.8 cm thick) cooked to an internal temperature of 17 or 77°C by conventional oven, convection oven or flat grill contained no motile trichinae, whereas chops cooked to 66°C sometimes contained motile trichinae. Chops cooked by either charbroil or deep fat fry and pretreated in a microwave oven sometimes had motile trichinae even after cooking to an end point of 77°C. Chops, which had been frozen for 18 hr at -23°C and were thawed by microwave to 0°C then deep fat fried to an end point temperature, sometimes had infectious trichinae as confirmed by tests with rats and mice. Additional research is underway to verify the thermal death times and temperatures for T. spiralis larvae.     

SENSORY ATTRIBUTES AND THIAMINE CONTENT OF ROASTING CHICKENS COOKED IN A MICROWAVE, CONVECTION MICROWAVE AND CONVENTIONAL ELECTRIC OVEN

Fresh whole roasting chickens were cooked to an internal temperature of 79°C (175°F) in either a microwave, convection microwave or conventional electric oven. The sensory attributes of breast meat samples from chickens cooked in the three ovens were evaluated by untrained and laboratory panels. Untrained panelists found convection microwave cooked samples to be more acceptable in terms of juiciness than microwave cooked samples. Laboratory panelists rated the chicken cooked in the conventional oven as significantly more tender and juicy but similar in flavor intensity to chicken cooked in the microwave ovens. Thiamine retention on a dry weight basis ranged from 77% in conventionally cooked chicken breasts to 98% in microwave cooked chicken legs.     

RETENTION OF VITAMIN B-6, THIAMIN,VITAMIN E,AND SELENIUM IN GRILLED BONELESS PORK CHOPS PREPARED AT FIVE GRILL TEMPERATURES1

Fresh pork Canadian backs, cut into boneless pork chops, were cooked to 71C internal temperature by grilling at 93, 121, 148, 176, or 204C. Cooking times were significantly longer for chops grilled at 93C than for those grilled at the higher temperatures. Yield, moisture, and crude fat values of the chops in the different treatments were similar. Chops grilled at 204C had significantly lower retention values for thiamin and vitamin E and had lower mean retention values for vitamin B-6. Retention values for selenium were similar for all treatment groups. Shorter cooking times along with higher vitamin retentions were obtained in boneless pork chops grilled at 121, 148, and 176C.     

Effect of Steam-Assisted Hybrid Cooking on Textural Quality Characteristics,Cooking Loss,and Free Moisture Content of Beef

Semitendinosus muscles were cooked in a steam-assisted hybrid oven and also convection ovens at three different oven temperatures (180, 210, and 240°C) until three different end point temperatures [65°C (medium-rare), 72°C (medium), 80°C (medium-well)] were reached. Textural properties of cooked beef were investigated by the Warner Bratzler shear test and texture profile analysis. Cooking loss and free moisture content of muscle tissue was determined for each cooking condition. In addition, sensory analysis was carried out in order to compare with the instrumental results and correlations between instrumental texture parameters and sensory results. Steam-assisted hybrid oven cooking of beef resulted in a tougher texture, higher cooking loss, and lower free moisture content than convection cooking. High correlation coefficients (r² > 0.70) were observed between instrumental texture measurements and sensory results for all ovens, especially in terms of tenderness. The free moisture content and adhesiveness values were also correlated well with juiciness (r² > 0.70) for all oven types.     

Effect of Microwave and Conventional Cooking on the Nutritive Value of Colossus Peas (Vigna uniguiculata)

The effect of microwave and conventional cooking methods, designed to simulate those used in home meal preparation, upon nutrient retention in Colossus Peas (Vigna uniguiculata) was studied. Neither method resulted in significant changes in the fat, protein, β-carotene and ascorbic acid content of the peas. Microwave cooking resulted in significantly greater losses of several ammo acids, but resulted in significantly greater retention of thiamin and riboflavin than the conventional treatment. Although each of the mineral components exhibited different magnitudes of loss by the two cooking methods, different due to method of cooking were not significant. Both Fe and Cu were completely retained in the peas cooked by both methods. Both cooking methods (15-60 min cooking) resulted in 92-97% loss of trypsin inhibitor.     

Effects of Frozen Storage and Cooking on Lipid Oxidation in Chicken Meat

Fresh chicken breast and leg meat samples, which were frozen for 3 months or 6 months at −18°C, were cooked in microwave and convection ovens and then tested for levels of lipid oxidation. After 6 months storage, malonaldehyde in fat from meat samples, as measured by a TBA assay, modified to avoid sample autoxidation, increased 2.5 fold, while the fluorescence excitation (360 nm) and emission (440 nm) spectra increased an average of 34%. Fat from meat cooked in a convection oven averaged 83% higher malonaldehyde concentration and 21% higher fluorescence compared to levels before cooking. Levels of lipid oxidation products in fat from chicken breast and leg meat were not significantly different in microwave compared to convection oven cooking; but certain secondary fluorescent products were higher in meats cooked by convection oven.     

Destruction of Trichinella spiralis During Cooking

Center cut chops (longissimus dorsi), 2.5 cm in thickness, from 31 pigs experimentally infected with Trichinella spiralis larvae and containing 37 ± 5 larvae per gram were cooked to a final internal temperature of 66, 71, 77 or 82° C by one of eight methods to determine their efficacy in killing encysted larvae. The results indicate that with the time and temperatures used in this study, some rapid methods of cooking pork chops that involved the use of a microwave oven did not completely destroy T. spiralis larvae at 77 or 82° C. The data also showed that cooking pork chops to an internal temperature of 77° C in the conventional oven, convection oven, flat grill, charbroiler or deep fat gryer did inactivate encysted T. spiralis larvae in pork chops.     

A Reasearch Note VITAMIN B6 IN PORK MUSCLE COOKED IN MICROWAVE AND CONVENTIONAL OVENS

Loin sections of pork muscle were heated to 75 or 85°C internal temperatures in microwave or conventional electric ovens. Cooking losses and time, percentage moisture and total vitamin B₆ were determined. Cooking time was longer, total cooking loss less and moisture content greater for pork cooked in an electric oven than for that cooked in a microwave oven. Differences in vitamin B₆ due to type of oven or internal temperature were small and not significant when calculated on a cooked weight basis. When calculated on a dry weight basis samples cooked in the conventional oven contained more vitamin B₆ than did those cooked by a microwave oven.     

Stability of Proteinase Inhibitors in Potato Tubers During Cooking

Three proteinase inhibitors, Inhibitor I (a chymotrypsin inhibitor), Inhibitor II (a chymotrypsin and trypsin inhibitor), and Carboxypeptidase Inhibitor were quantified immunologically in extracts of various tissues of Russet Burbank potato tubers and were monitored over various intervals during boiling (30 min), oven baking (80 min, 191°C) and microwave baking (7 min) to assess the effectiveness of cooking in denaturing the potentially toxic proteins. In cooked tubers, Inhibitor II was completely inactivated during all cooking treatments and Inhibitor I was partially inactivated, depending upon the cooking method. The Carboxypeptidase Inhibitor was extraordinarily stable during all of the cooking conditions. Overall, microwave baking was most effective for cumulatively inactivating Inhibitor I and Inhibitor II. The unusual stability of CPI to all types of cooking raises questions concerning the effect of this inhibitor on the total digestibility of cooked potato proteins.     

Validation of a Combi Oven Cooking Method for Preparation of Chicken Breast Meat for Quality Assessment

ABSTRACT: Quality assessment results of cooked meat can be significantly affected by sample preparation with different cooking techniques. A combi oven is a relatively new cooking technique in the U.S. market. However, there was a lack of published data about its effect on quality measurements of chicken meat. Broiler breast fillets deboned at 24‐h postmortem were cooked with one of the 3 methods to the core temperature of 80 °C. Cooking methods were evaluated based on cooking operation requirements, sensory profiles, Warner–Bratzler (WB) shear and cooking loss. Our results show that the average cooking time for the combi oven was 17 min compared with 31 min for the commercial oven method and 16 min for the hot water method. The combi oven did not result in a significant difference in the WB shear force values, although the cooking loss of the combi oven samples was significantly lower than the commercial oven and hot water samples. Sensory profiles of the combi oven samples did not significantly differ from those of the commercial oven and hot water samples. These results demonstrate that combi oven cooking did not significantly affect sensory profiles and WB shear force measurements of chicken breast muscle compared to the other 2 cooking methods. The combi oven method appears to be an acceptable alternative for preparing chicken breast fillets in a quality assessment.     

Evaluation of Microwave Cooking Procedures and Ovens for Devitalizing Trichinae in Pork Roasts

Pork roasts from pigs experimentally infected with Trichinella spiralis were cooked in five microwave ovens. Twenty-nine procedures, generally recommended by the oven manufacturers or pork interest groups, were used. Infective trichinae were present after cooking in 50 of 189 roasts. Factors affecting infectivity included procedure used, use or nonuse of post-cooking standing or temperature holding, weight of roast, and internal temperatures attained. Five visually well done roasts contained infective trichinae including one in which all five temperatures taken exceeded 76.7°C. One other infective roast, with a small red spot, also had all temperatures at or above the 76.7°C level. Recommendations are made to minimize the potential that trichinae may survive in microwaved-cooked pork.     

Effects of Electrical Stimulation, Boning Time and Cooking Method on Beef Roasts

Sixteen steer carcasses were selected to study effects of electrical stimulation, boning time and cooking methods on palatability traits, cooking loss and chemical composition of beef biceps femoris muscle. Eight carcasses were electrically stimulated and eight carcasses served as controls. The biceps femoris muscle was removed from one side of each carcass within 2 hr of exsanguination and from the remaining side following a 48-hr chill. Muscles were subdivided and cooked in either a convectional electric or a microwave oven. Electrical stimulation resulted in longer (P < 0.01) sarcomeres for cooked product but did not affect palatability traits, cooking loss or chemical content. Hot boning reduced (P < 0.01) cooking loss and tenderness, resulted in less (P < 0.05) total, soluble and insoluble collagen and increased the juiciness score and moisture percentage when compared with 48-hr boning. Microwave cooking produced a greater (P < 0.01) cooking loss and a higher shear force value than convectional electric cooking.     

Effect of Cooking on Cholesterol Content of Patties Containing Different Amounts of Beef, Textured Soy Protein and Fat

Ground beef patties were prepared to contain 0, 10, 20 or 30% rehydrated textured soy protein (TSP) and 8, 16 or 27% fat. Patties were cooked from the frozen state on a rack in a preheated oven at 177°C to an endpoint internal temperature of 75°C. The cholesterol content of raw ground beef patties decreased as the amount of TSP increased and also decreased as the fat content decreased from 27 to 16 or 8%. At initial fat levels of 8 and 16%, there were no significant differences in cholesterol retention (per-patty basis) during cooking among patties with initial TSP (rehydrated) levels of 0, 10, 20 and 30%; at an initial fat level of 27%, however, patties containing TSP (10, 20 or 30%) retained substantially higher (P < 0.05) amounts of cholesterol when cooked than did those without TSP.     

Nutrient retention in microwave cooked germinated legumes

The effects of germination on the cooking quality and nutrient retention in pressure and microwave-cooked Bengal gram, green gram and horse gram were studied. Ungerminated (UGL) and germinated legumes (GL) cooked in a microwave oven, and under pressure were analysed for moisture, protein, ash, iron, thiamin, ascorbic acid, in vitro protein digestibility (IVPD) and starch digestibility (IVSD) and bioavailable iron. Results revealed that microwave cooking required more water and time than did pressure cooking. The range of analysed constituents on dry weight basis in UGL and GL legumes, respectively, were as follows: protein, 18.2–23.5 and 19.4–25.7 g, ash, 2.1–2.9 and 2.2–2.9 g, iron, 5.4–7.3 and 7.3–10.3 mg, thiamin, 0.10–0.34 and 0.54–1.83 mg, ascorbic acid, 2.4–3.9 and 3.1–25.6 mg/100 g. The effect of germination and method of cooking on nutrient retention varied, depending on nutrient and severity of heat treatment. Microwave cooking caused 36–57% reduction of ascorbic acid while pressure cooking caused 10–30% loss. The IVSD in raw samples ranged from 18.4% to 22.1% in UGL and 33.6% to 43.6% in GL. Cooking of UGL and GL, by both methods, increased the starch digestibility threefold. The IVPD of raw UGL ranged from 64.6% to 66.2% and that of GL was 72.4–73.9%. In cooked UGL the IVPD ranged from 70.9% to 82.3% and, in GL, from 78.4% to 84.2%, showing a significant difference in cooking methods only in UGL. The iron bioavailability ranged from 11.5% to 18.7% in raw UGL while it was 18.3–20.6% in GL. GL had a higher content of thiamin and ascorbic acid, higher protein and starch digestibility and bioavailable iron, even after cooking.     

Stability of Polyunsaturated Fatty Acids after Microwave Cooking of Fish

The stability of fish oils high in polyunsaturated fatty acids (PUFA) in fresh fish of low, medium and high fat content was investigated using microwave oven cooking. Cooked and uncooked portions of butterfish, mullet, mackerel and sardines were extracted, the lipid recovered and fatty acid composition determined. The effect of cooking was minimal with no detectable difference in total lipid between cooked and uncooked samples. Most important, PUFA were virtually unaffected by the overall cooking and the cooked fish retained their original PUFA composition and content.     

Power and Cooking Time Relationships for Devitalization of Trichinae in Pork Roasts Cooked in Microwave Ovens

Power and cooking time combinations necessary to devitalize trichinae in pork roasts were determined using three power levels in each of two microwave ovens. The combinations obtained for an oven listed as producing 700 watts were: 100% power, 19.8 min/kg; 70%, 24.2 min/kg; and 30%. 55.0 min/kg. Those for a listed 625 watt oven were: 100% power, 24.2 min/kg; 70%, 26.4 min/kg; and 30%, 55.0 min/kg. Inadequate doneness in many roasts cooked with the safe combinations would necessitate additional cooking time before procedures could be recommended. Post-cooking temperatures during a 20-min standing period may either increase or decrease with no predictability.     

Thiamin Retention and Other Characteristics of Cooked Beef Loin Roasts

Beef loin roasts were prepared by three procedures that simulated home, foodservice or commercial methods for precooking meat prior to vacuum packaging. Roasts were prepared by conventional electric (176.5°C), cook-in-package waterbath (70°C water), or smokehouse (ambient temperature) heating. Yield, thiamin, fat, water content, and Instron tenderness of roasts were determined. Raw roasts had higher (P<0.05) water and free water content. All cooked roasts were significantly lower in thiamin content (dry, fat free basis) and thiamin retention (true and dry, fat free basis) than raw roasts (P<0.05). No differences were observed between cooking procedures evaluated (P>0.05), suggesting that most heat processing treatments used for precooking packaged meat result in similar quality products.     

Effect of Storage and Cooking on Qualities of Loin and Top-Wound Steaks

SUMMARY— Boneless, trimmed steaks (U. S. Good) from the longissimns dorsi muscle (loin) and semimembranosus muscle (top-round) and conventionally cut loin steaks were removed 8 days post-mortem, quick-frozen and stored at −18°C to −23°C for three storage periods, 0, 6, and 9 months. Steaks were sampled at each storage period and cooked to an internal temperature of 70°C in a microwave oven and electric range. Quality was evaluated by chemical tests, sensory evaluations and cooking loss data.
Storage up to 6 months had little effect on loin steaks with the exception of TBA values, but significant changes occurred between 6 and 9 months. Loin steaks had increased cooking losses and decreased juiciness scores, percent moisture, and juice content. TBA values increased with each storage period. Top-round steaks at the 9-month period showed a decrease in collagen content and juiciness and flavor scores, and an increase in TBA values. Storage up to 9 months did not influence tenderness in either muscle.
Conventionally broiled loin steaks had higher palatability scores, cooking losses, percent moisture, percent total proteins, and lower percent total lipids than did microwave cooked loin steaks. Electronically cooked top-round steaks had higher total cooking losses and percent total proteins and lower collagen values than did conventionally roasted top-round steaks.
The qualities of boneless loin steaks did not differ significantly from those of conventionally cut loin steaks when compared at each storage period.