EFFECT OF GAMMA RAY IRRADIATION AND FRYING ON THE THIAMINE CONTENT OF BACON

The effects of ionizing irradiation and frying on the thiamine and riboflavin content of bacon were determined. Significant destruction of thiamine but not riboflavin occurred during both the irradiation and frying. The destruction of thiamine was found to be directly related to the dose of ionizing radiation or the degree of cooking. Frying before irradiation, reduction of water content by lyophilization, and irradiation at - 40°C rather than 2°C produced significantly greater retention of thiamine. Frying the bacon following irradiation produced radiation dose-related, nonadditive, increased destruction of thiamine. The protective effect of frying before irradiation was not directly linked with the reduction of moisture by frying.     

Thiamin in bestrahlten Lebensmitteln

Zusammenfassung Die Wirkung von 10 MeV-Elektronenstrahlen, mehrmonatiger Lagerung und Erhitzen auf den Thiamingehalt von Weizenmehl, Haferflocken, Schweine-Hackfleisch und Trockenvollei wurde untersucht. Die Kombination dieser Behandlungen wirkt synergistisch auf den Thiaminverlust. Durch Lagerung und Erhitzen wurde der Thiamingehalt in bestrahlten Proben stärker vermindert als in urbestrahlten.

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Thiamine in irradiated foodstuffsII. Combined effects of irradiation, storage and cooking on the thiamine content

Summary The effects of 10 MeV electron radiation, of storage for several months and of heating on the thiamine content of wheat flour, crushed oats, ground pork, and dried whole egg were studied. A synergistic effect of these treatments on thiamine losses was observed. In irradiated samples thiamine content was more affected by storage and heating than in unirradiated ones.

     

Changes in the nutritive value of food products after thermal culinary handling

The data were summarized for the first time concerning the losses of the basic food substances (protein, fats, carbohydrates, Na, K, Ca, Mg, P, Fe, vitamins A, B1, B2, PP, C) and caloric value as a result of the different methods of culinary treatment: cooking, frying, stewing, baking, and so forth. It was shown that the greatest losses of vegetable foods are observed during frying, those of animal foods during cooking. It was also shown that the least losses of nutritive substances of vegetable foods are observed during cooking without water pouring off. The losses of nutritive substances of animal foods were minimal during stewing, baking and cooking in the form of cutlets. For rough estimation of the daily diet the losses during thermal culinary treatment may be assumed on the average as 6% (proteins), 12% (fats), 9% (carbohydrates), and 10% (the caloric value).     

Effect of cooking on the nutritive value of koko/kosai—A traditional breakfast meal of the hausas in Northern Nigeria

The effect of cooking on the nutritive value of koko/kosai was assessed by chemical analysis. There was significant loss in the proximate composition due to cooking. In addition, losses of some mineral elements and vitamins were observed. The losses in potassium, iron, zinc and phosphorus were found to be 23%, 6·7%, 25% and 13·3%, respectively.Losses of vitamins B₁, B₂, C and carotene were found to be 20%, 46%, 37% and 9·6%, respectively.The amino acid pattern of the koko/kosai was only slightly affected by the traditional method of cooking employed. Some suggestions and recommendations are made on how to retain most of the nutrients when cooking the meals.     

Effect of Pressure Cooking and Pressure Rate Change during Cooling in Vacuum on Chicken Breast Quality and Yield

The effect was studied of processing time, weight loss, quality, cooking in steam at a pressure of 1.03 or 0.345 bar and cooling at different pressure reduction rate (0.6 to 0.07 bar/minute) on chicken breasts quality. Heating time was not affected by cooking pressure but cooling time was reduced as pressure reduction rate increased. Weight losses varied from 26.4 to 37.7% and increased with severity of temperature-time treatment. Tenderness was not affected by cooking/cooling but juiciness decreased with increased pressure and reduced cooling rate. Juiciness correlated with weight loss (r = - 0.72). A 9 member sensory panel indicated harsher temperature-time treatments gave more acceptable meat.     

Quality Characteristics of Restructured Beef Steaks Manufactured by Various Techniques

Beef (9–11% fat) was restructured with each of six mechanical treatments including chunking, fiberizing, slicing, chunking + slicing, slicing + water, and tenderizing each in combination with addition of 0.5% sodium chloride (salt)/0.5% phosphate, 0.5% Na-alginate/0.5% Ca-lactate, 0.5% Na-pectate/0.5% Ca-lactate, or no additives (control). Beef steaks restructured with salt/phosphate had lower (P<0.05) purge losses: higher binding force and bind scores than control products. Steaks restructured with Na-alginate/Ca-lactate had lower cooking losses and higher bind scores than controls. Use of Na-pectate/Ca-lactate did not improve (P>0.05) purge loss, cooking loss, binding force or sensory properties. Chunked meat or mixtures of chunked and sliced meats in combination with salt/phosphate or Na-alginateica-lactate resulted in steaks with acceptable bind and textural properties.     

海藻油、鱼油和DHA调和油在烹调过程中DHA损失研究

为确定海藻油、鱼油及DHA调和油在烹调过程中DHA的损失情况,模拟烹调环境,对海藻油、鱼油和DHA调和油进行了比较研究.结果表明:海藻油、鱼油在加热条件下DHA损失较大;而将海藻油、鱼油添加到植物油中作为含量相对较低的DHA植物调和油时,在加热及烹调环境中DHA损失会大大降低,在一般家庭烹调炒菜条件下,DHA损失率在5％以内,保留率超过95％.     

The influence of processing and preservation on the retention of health-promoting compounds in broccoli

ABSTRACT:  In this work the effects of common household practices such as chilling, freezing, and cooking on vitamin C retention in broccoli (Marathon cv.), as well as their influence on the release of sulforaphane upon enzymatic hydrolysis of glucoraphanin by the endogenous enzyme myrosinase, were investigated. When chilled at 6 °C and 95% R.H. for 35 d, broccoli showed a vitamin C and sulforaphane loss of about 39% and 29%, respectively, while storage at –18 °C for 60 d resulted in similar losses, but mainly due to the blanching step. Boiling, steaming, microwaving, pressure-cooking, and the combined use of pressure and microwaves were the cooking methods investigated. Boiling and steaming caused significant vitamin C losses, 34% and 22%, respectively, while with the other treatments more than 90% retention was observed. Sulforaphane was no more detectable after boiling or steaming, while pressure/microwave cooking did not cause any significant loss. The quantitative distribution of these moieties in the florets and stems of fresh and chilled broccoli was also investigated.     

Mechanisms of Docosahexaenoic and Eicosapentaenoic Acid Loss from Pacific Saury and Comparison of Their Retention Rates after Various Cooking Methods

The docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents of Pacific saury (Cololabis saira), a fatty fish and staple of the Japanese diet, have been reported to decrease after cooking. This study compared the DHA and EPA contents remaining in saury after grilling, pan‐frying or deep‐frying to center temperatures of 75, 85, or 95 °C, and examined physical loss, lipid oxidation, and thermal degradation as mechanisms of DHA and EPA loss. Temperature changes inside the saury were monitored using thermocouples, while DHA and EPA contents, oxygen radical absorbance capacity, and measurements of lipid oxidation (that is, carbonyl value and thiobarbituric acid value) were determined chemically. Visualization of temperature distribution inside fish samples during cooking revealed large differences in heat transfer among cooking methods. True retention rates in grilled (DHA: 84 ± 15%; EPA: 87 ± 14%) and pan‐fried samples (DHA: 85 ± 16%; EPA: 77 ± 17%) were significantly higher than deep‐fried samples (DHA: 58 ± 17%; EPA: 51 ± 18%), but were not affected by final center temperatures despite differences in cooking times. Physical loss via cooking losses (grilling and pan‐frying) or migration into frying oil (deep‐frying) accounted for large quantities of DHA and EPA loss, while lipid oxidation and thermal degradation did not appear to be major mechanisms of loss. The antioxidant capacity of saury was not significantly affected by cooking treatments. The results of this study suggest that minimization of physical losses during cooking may increase DHA and EPA contents retained in cooked Pacific saury.     

热塑挤压蒸煮处理对鱼肉蛋白质消化率的影响

采用胃蛋白酶-胰酶复合处理法对几种热加工处理的鱼肉制品进行蛋白质体外消化率的测定,从蛋白质消化率角度,将热塑挤压蒸煮处理与3种传统热加工处理进行比较,了解几种热加工处理对鱼肉蛋白质营养价值的影响。研究结果发现,热塑挤压蒸煮处理方法比3种传统热加工处理方法更能提高鱼肉蛋白质的消化率,进而表明热塑挤压蒸煮处理方法比3种传统热加工处理方法有利于提高鱼肉蛋白质的营养价值。     

不同冷冻方式对淡水鱼品质的影响

为了研究不同冷冻方式对淡水鱼品质的影响,以鮰鱼、鲈鱼、鳜鱼为研究对象,采用－30?℃平板、－80?℃冰箱和－80?℃液氮分别对鮰鱼、鲈鱼、鳜鱼进行冷冻处理,考察了不同冷冻方式对鮰鱼、鲈鱼和鳜鱼的解冻损失率、加压失水率、蒸煮损失率、pH值、色泽、韧性、微观组织结构、水分分布等指标。结果表明：经过－30?℃平板冷冻、－80?℃冰箱和－80?℃液氮处理后,同种淡水鱼解冻损失率、加压失水率、蒸煮损失率呈现下降趋势,其韧性呈现增大趋势,pH值无显著性变化,细胞间隙呈现下降趋势;对于同种淡水鱼,－30?℃平板冷冻组的白度最高,－80?℃冰箱和－80?℃液氮组间无显著差异（P＞0.05）;低场核磁共振结果表明,对于同种淡水鱼,相对其他两种冷冻方式,－30?℃平板冷冻处理组样品的不可移动水（T22）含量下降,自由水（T23）含量显著升高（P＜0.05）;对于不同淡水鱼,经同种冷冻方式处理后其相关指标间差异性较小。从冷冻速率和品质考虑,选择－80?℃冰箱和－80?℃液氮处理更有利于保持淡水鱼的品质。     

CHEMICAL AND PHYSICAL CHANGES IN IRRADIATED AND FROZEN BOMBAY DUCK

SUMMARY— Bombay duck (Harpodon nehereus), a tropical fish, is readily susceptible to drip losses leading to textural alterations. These changes occur during storage at 0 or −20°C for 3 days and also by irradiation and storage at 0 or 10°C for 3 days. In situ denaturation of fibrillar proteins of Bombay duck occurs as evidenced by a decrease in salt-soluble proteins. Loss in extractability occurring at 0 or −20°C parallels increased drip loss, but appears to be arrested by pre-dip treatment in 10% sodium tripolyphosphate solution for 15 min. The radiation-induced drip loss also correlates with loss in the extractability at a radiation dose of 3 Mrad, but at 0.5 Mrad the drip loss occurs without appreciable decrease in the extractability. Pre-dip treatment in 10% sodium tripolyphosphate solution reduces the drip loss caused by 3 Mrad, but this is not reflected in the recovery of extractable proteins. Loss in the extractability could be attributed to the aggregation phenomenon of fibrillar proteins induced by irradiation. The radiation-induced off-odors appear to originate from the sarcoplasmic proteins.     

Thiamine in irradiated foodstuffs. II. Combined effects of irradiation, storage and cooking on the thiamine content (author's transl)]

The effects of 10 MeV electron radiation, of storage for several months and of heating on the thiamine content of wheat flour, crushed oats, ground pork, and dried whole egg were studied. A synergistic effect of these treatments on thiamine losses was observed. In irradiated samples thiamine content was more affected by storage and heating than in unirradiated ones.     

Effect of cooking and irradiation on the labile vitamins and antinutrient content of a traditional African sorghum porridge and spinach relish

Irradiation is a potentially useful technology for ensuring the safety and extending the shelf-life of food products in Africa. However, nutritional changes may result. The effects of cooking followed by irradiation (10 kGy) on vitamins B₁ and C, and the antinutritional factors, phytic acid and nitrates, in a ready-to-eat meal of sorghum porridge and spinach-based relish were investigated. Cooking reduced vitamin B₁ and C contents of the spinach relish, and irradiation caused further losses. Cooking did not alter vitamin B₁ content of the sorghum porridge but irradiation decreased it drastically. Cooking did not decrease phytic acid in the sorghum porridge, but irradiation caused a significant decrease. The reduction of antinutritional factors by cooking, followed by irradiation, is promising for the application of this technology to traditional African cereal and leafy vegetable foods. However, ways need to be found to minimise vitamin loss, such as blanching and cooking in minimum water and irradiation at cryogenic temperatures in an oxygen-free atmosphere.     

Influence of cooking conditions on cooking loss and tenderness of raw and marinated chicken breast meat

The influence of different cooking treatments on tenderness and cooking loss, as main quality characteristics of chicken breast meat, was investigated. Industrial skinless chicken breast meat samples were designated as raw and marinated and cooked in the oven by hot air and hot air-steam mixture at 130, 150 and 170 °C, for 4, 8 and 12 min. Cooking losses were evaluated by weight changes before and after cooking, and tenderness changes were determined on cooked samples by measuring shear force using instrumental texture analysis. Results showed that marination, followed by air-steam cooking is the best combination to obtain the most tender chicken breast slices. The time and temperature of cooking showed similar effects on cooking loss and tenderness: short cooking time (4 min) and temperatures of 130–150 °C resulted in lower cooking losses and best meat tenderness, in both not marinated and marinated meat. Statistically significant correlations between tenderness and cooking loss indicated that the cooking loss correlated better with cooking time than with cooking temperature. An opposite phenomenon was observed for meat tenderness.     

Thiamine in irradiated foodstuffs I. Influence of different radiation conditions and of time after irradiation]

Effects of 10 MeV-electron radiation on thiamine dichloride in crystalline form and in solution, and on thiamine in dried whole egg are described. Both in the dry state and in aqueous solutions, radiation induced reactions continue to affect thiamine over a considerable period of time after irradiation. Thiamine losses decrease in the order: dry thiamine dichloride, aqueous solution, hydrochloric acid solution, dried whole egg.     

Changes in the vitamin content of various cereals during storage

Thiamine and niacin losses were studied in various cereals (grinding millet, non-grinding oatmeal, fine-ground corn, grinding rice, wheat Poltavskaya, buckwheat, pearl-barley, and grinding pea) stored in sacks at store-houses in two different climatic areas of the USSR - with a temperate and with a dry hot climate, as well as at a constant temperature of 10 degrees C, during 6-29 months. Vitamin losses in grinding millet, non-grinding oatmeal and grinding rice were evaluated considering their treatment with methyl bromide and cereal cooking. It was found that during the storage under conditions of a dry hot climate thiamine and niacin losses comprised 37.8, after methyl bromide treatment - 44.0, and after cooking - 28.6%. Lower vitamin losses were recorded after the cereals storage at a constant temperature of 10 degrees C.     

Effects of cooking method, reheating, holding time, and holding temperature on beef longissimus lumborum and biceps femoris tenderness

Effects of cooking method, holding temperature, holding time, and reheating on Warner-Bratzler peak shear force (WBPSF); Warner-Bratzler myofibrillar force (WBM-F), Warner-Bratzler connective tissue force (WBC-F) and cooking loss were investigated. Two muscles (longissimus lumborum and biceps femoris) from USDA Choice beef carcasses were used. Water-bath cooking resulted in higher WBPSF, WBM-F, and WBC-F than belt-grill cooking for longissimus lumborum. The biceps femoris muscle tenderness improved more with holding time after cooking on a belt than the longissimus lumborum due to its higher collagen content. Cooking biceps femoris steaks to 54?°C by a belt grill and holding them at 57?°C in a water bath for 15 min and subsequent reheating to 70?°C (best treatment combination) produced a 25% reduction in WBPSF, a 37% reduction in WBC-F, and a 12% reduction in WBM-F as compared to the control (cooking steaks directly to 70?°C without holding). Water-bath cooking resulted in lower WBPSF than belt-grill cooking for biceps femoris without any holding time, but further tenderization did not occur with holding. Water-bath cooking resulted in higher cooking losses than belt-grill cooking for both muscles.     

Effect of domestic processing on flatus producing factors in ricebean (Vigna umbellata)

The effect of various processing treatments viz., soaking, pressure cooking, open pan cooking, germination followed by pressure cooking and roasting of whole ricebean and pressure cooking, open pan cooking and fermentation and frying of fermented batter of dehulled ricebean flour was assessed for total sugars and oligosaccharide contents. Dehulling caused a significant reduction in the raffinose and stachyose contents. Pre-soaking of ricebean caused appreciable losses in the oligosaccharide content. Germination (48 h) followed by pressure cooking and fermentation (18 h) followed by frying caused the maximum losses in the raffinose and stachyose contents.     

Studies on emulsion-type buffalo meat sausages incorporating skeletal and offal meat with different levels of pork fat

Ready-to-eat emulsion-type buffalo meat sausages were developed by using a combination of 80% meat components with 20% pork back fat. The meat components were constituted of 70 parts buffalo skeletal meat and 30 parts offal meat (rumen meat and heart meat in equal proportions). The emulsion stability, cooking losses of emulsions and sausages, composition of cooked sausages, eating quality of sausages and the microscopic characteristics of the raw emulsion and cooked sausages were studied. The light microscope micrograph of the raw emulsion showed uniformly well distributed fat globules embedded in a dense protein gel. The cooked emulsion also showed uniformly sized fat globules well distributed in a fine, compact, coagulated protein gel, which retained their original spherical shape. Good quality emulsion-type sausages could be produced having a high emulsion stability (0·87 ± 0·07 ml fat release/100 g emulsion); a low emulsion cooking loss (9·60 ± 0·60%) and a low sausage cooking loss (8·83 ± 0·48%). The overall acceptability of sausages was also high.