Nutritional value and digestion rate of rhea meat proteins in association with storage and cooking processes

The nutritional value of proteins was investigated after the storage and cooking of rhea M. Gastrocnemius pars interna. Oxidation of basic and aromatic amino acids, surface hydrophobicity and aggregation state of proteins, were determined in raw and cooked meat. In addition, myofibrillar proteins were exposed in vitro to proteases of the digestive tract. Cooking markedly affected the protein surface hydrophobicity. The BBP bound content was three times greater in cooked than in fresh rhea meat. A small increment in tryptophan content after cooking was observed. Storage influenced Schiff bases formation indicating the presence of protein-aldehyde adducts after cooking. High content of Schiff bases was found after cooking of samples stored for 5 days, demonstrating a probable implication of free amino groups, most likely from lysine. Cooking decreased the myofibrillar protein susceptibility to pepsin activity. After cooking, the proteolysis rate by pancreatic enzymes increased. Our findings support the importance of protein aggregation in the nutritional value of meat proteins.     

The properties of trona and its effect on the cooking time of cowpeas

Trona (Urao) popularly known in Ghana as kawe is used for medicinal and tenderiser purposes (especially in reducing the cooking time of cowpea). The type of kawe found in Ghana contained predominantly 25.0% sodium with small amounts of other metals. Cooking cowpeas in the presence of kawe reduced the cooking time from 75 to 50 min which represents a saving of time and fuel to the cooker.     

烹饪方式对马铃薯营养成分和生物活性物质影响的研究进展

马铃薯是全球重要的粮食作物,富含营养成分和生物活性物质。马铃薯通常采用煮、蒸、炸、烘焙等烹饪方式。在不同烹饪过程中马铃薯的物理、化学性质和酶活性的变化不同,从而影响马铃薯的营养成分和功能作用。本文综述了不同烹饪方式对马铃薯的营养成分及生物活性物质的影响,分析了烹饪方式对马铃薯抗氧化、抗癌症、调节血糖等功能影响的研究进展,以期为马铃薯的精深加工、综合利用提供参考依据。     

Quality changes and mineral composition of African yam bean (sphenotilis sternocarpa) cooked in kaun (trona) solution

Some quality attributes (cooking time, water absorption and organoleptic qualities), pH, chemical and mineral composition of African yam bean (AYB) cooked in “kaun” solution have been investigated. Cooking in different concentrations of kaun at atmospheric pressure and longer cooking time generally increased water absorption but the optimal cooking conditions (i. e. best kaun concentration and minimum cooking time to achieve optimal quality) were found to be 0.1% and 90 minutes respectively. Cooking in kaun solution of concentration higher than 0.1% caused an unappealing deep brown colour, less number of splitted beans or even no splits and decreased softening of the beans. While cooking in kaun solution at the optimal conditions at atmospheric pressure increased the concentrations of Zn, Ca, Fe, Na and K in both the cooked beans and leached solids, it decreased the concentration of Mg and Cu in the cooked beans. Cooking in kaun solution was also found to produce some little changes in proximate composition. Explanations on the mechanism of softening of the beans in kaun solution were discussed.     

A comparative study of the nutritional values,volatiles compounds,and sensory qualities of pea pastes cooked in iron pot and clay pot

In the current study, the nutritional values, volatiles compounds, and sensory qualities of pea pastes cooked in iron pot and clay pot were compared. Results showed that the iron pot‐cooked pea pastes contained profoundly more iron, total sugar, and starch than the clay pot‐cooked ones, and the effects were found related to iron ion by comparing the results between clay pot‐cooked pastes with and without iron ion addition. Samples prepared with the two utensils demonstrated similar contents of protein, polyphenol, and tannin, but differed in the composition of some volatile alcohols, alkanes, aldehydes, ketones, esters, and organic acids. The clay pot‐cooked samples had higher score of “color,” “mouthfeel,” “taste,” and “overall quality” than the iron pot‐cooked pastes. In conclusion, iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in the acceptable range.

Practical applications

Iron utensil plays an important role in modern food industry due to its durability and convenience to handle. Cooking with iron pot is a simple and useful method of dietary iron fortification for the prevention of iron‐deficiency anemia in developing countries. Pea paste is a popular legume food with high nutritional value and good palatability. Traditional pea paste producers believe cooking with clay pots can give rise to product with more desirable features than using iron pots. However, there were no scientific evidences regarding the effects of cooking utensils on pea paste qualities. It has been proved in the current study that iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in acceptable range.     

甘蔗渣制茶工艺优化

本研究利用甘蔗榨汁后的甘蔗渣制作甘蔗茶,通过二次回归正交旋转组合试验探讨了炒制温度、炒制时间和转速对甘蔗茶感官评分的影响,确定最优制作工艺条件,并测定最优制备工艺下甘蔗茶营养成分含量。结果表明,炒制温度为127 ℃,炒制时间33 min,转速为60 r/min时,在此条件下,甘蔗渣制茶工艺最优,感官评分为92.47分,感官评价良好,此时甘蔗茶营养成分含量分别为:脂肪0.25%±0.06%,蛋白质1.99%±0.39%,还原糖7.26%±0.38%,水分6.48%±0.27%,灰分1.89%±0.20%,该研究可为甘蔗渣利用提供参考。     

Changes of Selected Physical and Chemical Components in the Development of the Hard-to-Cook Bean Defect

The effects of storage temperature and humidity were monitored on several physical and chemical components of cowpeas and beans. Seeds stored at 29°C, 65% RH required prolonged cooking times; however, seeds stored in other conditions (5°C, 30% RH; 29°C 30% RH; and 5°C, 65% RH) maintained short, stable cooking times throughout storage. As cooking time increased, phytate, phytase activity, amylose solubility, high methoxyl pectin and protein solubility decreased. Solids leached during soaking and low methoxyl pectin increased as cooking time increased. These results were consistent with the proposed theory that the hard-to-cook defect involves interactions between phytate, minerals, and pectin. However, they did not eliminate possible roles of starch and protein solubility.     

Micronisation and hot air roasting of cowpeas as pretreatments to control the development of hard-to-cook phenomenon

BACKGROUND: Cowpeas stored under conditions of high temperature and high relative humidity (HTHH) develop the hard‐to‐cook (HTC) defect. Cowpeas with HTC defect require long cooking times, limiting their utilisation. Heat pretreatments are aimed at inactivating the enzymes responsible for HTC defect development. In this study, two heat pretreatments, micronisation and hot air roasting, were evaluated to assess their effectiveness in controlling the HTC defect development in cowpeas after storage under HTHH conditions. RESULTS: Micronisation and hot air roasting as pretreatments reduced the cooking time of cowpeas after storage under HTHH conditions compared with the control. The differences in the effectiveness of HTC defect control between micronisation and roasting were dependent on the degree of phytase inactivation on day 0. Phytase activity was reduced by 45 and 70% by roasting and micronisation pretreatments respectively. Reduced phytase activity was associated with higher phytate and soluble pectin contents in micronised cowpeas than in roasted cowpeas after HTHH storage. This observation is in agreement with the phytase‐phytate‐pectin theory. CONCLUSION: Micronisation was more effective than hot air roasting in controlling the development of HTC defect. This was due to a higher degree of phytase inactivation in micronisation when compared with roasting. Copyright © 2011 Society of Chemical Industry     

Sodium Lactate Effect on Sensory Characteristics, Cooked Meat Color and Chemical Composition

Cooked, vacuum packaged beef top rounds injected with 0, 1, 2, 3 or 4% sodium lactate were stored up to 84 days at 0°C. Cooking yields and chemical composition were determined initially, while changes in sensory attributes, Warner-Bratzler shear force and color were evaluated after 0, 14, 28, 42, 56, 70 and 84 days storage. Increasing sodium lactate resulted in higher cooking yields and darker, redder color with less gray surface area. Flavor notes associated with fresh beef were enhanced by addition of sodium lactate, and flavor deterioration during storage was minimized. Palatability was improved by adding 1% sodium lactate, but beyond 1 to 2% it did not further improve. Changes in cooked meat tenderness were verified by Warner-Bratzler shear force measurements.     

Muscle Microstructure and Sensory Attributes of Organic Acid-Treated Beef Strip Loins

Beef strip loins were cut into halves and one-half sprayed with a 2% lactic and acetic acid mixture (v/v) and corresponding halves used as controls. Strip loins were stored at – 1°C for 0, 7, 14, 28, 56, 84, or 112 days and evaluated for sensory and microstructural properties. Cooking loss and Hunter color ‘L’ values decreased (P<0.01) and thiobarbituric acid reactive substances (TBARS) increased (P<0.01) over 112 days. No differences (P>0.05) were detected for cooking loss, shear force, TBARS, or Hunter color values between treatments. Flavor intensity increased (P<0.05) over time; however, no other sensory differences (P>0.05) were noted for storage time or acid treatment. Organic acids appeared to denature muscle microstructure without having any effects on physical and sensory attributes.     

Effects of Long-term Storage on Sensory and Nutritional Quality of Rolled Oats

Sixteen samples of regular and quick‐cooking rolled oats stored up to 28 y in a reduced oxygen atmosphere in nr 10 cans at ambient temperatures were analyzed for sensory and nutritional quality. A consumer panel evaluated aroma, texture, flavor, aftertaste, and overall acceptability using a 9‐point hedonic scale. Hedonic scores varied from 4.8 to 6.7. Although there was a loss of sensory quality in samples over time, all samples were considered acceptable by at least 3/4 of panelists for use in an emergency. Vitamin B₁ amounts ranged from 2.7 to 6.6 μg/g and were highest in some older samples. Vitamin E amounts ranged from 1.3 to 37.8 μg/g and were negatively correlated with headspace hexanal levels. Rolled oats can be included in long‐term food storage regimens because of their sensory and nutritional stability when properly packaged and stored.     

Reversibility of the Hard-to-Cook Defect in Dry Beans (Phaseolus vulgaris) and Cowpeas (Vigna unguiculata)

The hard-to-cook defect, assumed to be a permanent condition in legume seeds, can be reversed. Dry beans (Phaseolus vulgaris) and cowpeas (Vigna unguiculata) which had developed the hard-to-cook defect when stored at 29°C, 65% RH had progressively shorter cooking times after additional storage at 6.5°C, 71% RH. This would suggest that the mechanism(s) leading to development of the defect should be easily reversed. The ability to reverse the hard-to-cook defect in legume seeds would provide several economic and nutritional benefits.     

Effect of soaking,germination, cooking and fermentation on antinutritional factors in cowpeas

The present work deals with the study of efficacy of some treatments, namely soaking (in water and bicarbonate solution( ordinary and pressure cooking, germination and fermentation in reducing or removal of antinutritional factors usually present in cowpeas (protease inhibitors, tannins, phytic acid and flatus‐producing oligosaccharides (raffinose and stachyose). The results showed that long‐time soaking (16 h) in bicarbonate solution caused remarkable reduction in the antinutritional factors. Pressure cooking was more effective than ordinary. Cooking pregerminated cowpeas was most effective. Fermentation completely removed trypsin inhibitor, oligosaccharides and reduced remarkably phytic acid. However, tannins noticeably increased.     

Microscopic, Nutritional and Functional Properties of Cowpea Flours and Protein Concentrates During Storage

During storage for 6 mo at 64% RH, whole seed flour, dehulled seed flour and air-classified protein concentrate from cowpeas showed little change in nutritional or sensory properties but there were improvements in functional properties. However, wet-processed protein concentrate, after drum-drying, darkened and had reduced functionality by the 6th mo. When storaged at 79% RH, all cowpea products darkened significantly, showed decreased lysine contents and lower nitrogen, solubility, all emulsification and foaming characteristics. Both dehulling and air classification improved the storage properties of cowpea products but drum drying of a wet-processed product had an adverse effect on functionality and nutritive value, especially when stored at 79% RH.     

Physicochemical and fatty acid characteristics of stewed pork as affected by cooking method and time

This study was designed to investigate the effects of cooking on physicochemical and fatty acid characteristics of stewed pork. Pre‐fried or raw pork belly cubes were stewed for 60, 90, 120, 150 or 180 min. After cooking, proximate chemical composition, texture, sensory evaluation, lipid oxidation, fatty acid profiles and cholesterol content were determined. Prolonged cooking time resulted in higher percentages of dry matter, fat and fat loss in stewed cubes (P < 0.01), and pre‐frying also increased fat loss. Tenderness and elasticity values of texture profile analysis and sensory scores were the highest for the cubes stewed for 180 min or by pre‐frying combined with stewing for 150 min. Pre‐frying and extended cooking time significantly increased lipid oxidation (P < 0.01). Cooking modified fatty acid profiles which altered the derived cardiovascular indices, and reduced cholesterol content. Prolonged stewing improved eating quality and most nutritional values of pork belly.     

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.     

Effects of harvesting procedure,storage time and climatic conditions on cooking time of lentils (Lens culinaris Medikus)

In an experiment conducted over 2 years in Larissa, the effects on the cooking times of six lentil varieties of different harvest periods (early and late), seed storage for 1 year and climatic conditions prevailing during seed production were studied. Cooking time was estimated by measuring seed hardness using a penetrometer (PNR‐6). Late harvesting (when the plants were completely dry) increased cooking times by 6–16% in comparison with early harvesting (when the plants were partly green). This increase was less for the short‐cooking genotypes ‘Dimitra’, ‘Samos’ and ‘Thessalia’ than for the long‐cooking genotypes ‘Arachova’ and ‘Nikaia’. After 1 year of seed storage, cooking times increased on average by 6–9%. Seeds produced during a dry year (1995) required on average 38% less time to cook than seeds produced during a wet year (1996), irrespective of harvest period or duration of seed storage. © 2001 Society of Chemical Industry     

The cooking qualities of microwave oven cooked instant noodles

Deep‐fried instant noodles were cooked in a microwave oven at 557 W (medium power) and 657 W (full power). The microwave cooking times were determined based on textural parameters and the qualities of microwave oven cooked noodles at medium power and full power were compared with those of products cooked using a conventional gas stove for 9.1 min (CON). Heating in the microwave increased the temperature of the noodle block faster than the cooking water, led to an increased degree of gelatinisation of instant noodles, and reduced the cooking times to 8.5 min (medium power) and to 7.5 min (full power). Cooking in the medium power microwave resulted in high water absorption and weak hardness values. Cooking in the full power microwave resulted in higher hardness and tensile strength than the medium power microwave and sensory evaluated organoleptic scores were comparable to the CON, despite having a significantly higher rancidity.