Steam Assisted Hybrid Cooking Behavior of Semitendinosus Muscle: Heterocyclic Amines Formation,Soluble Protein Degradation,Fat Retention,Surface Color,and Cooking Value

Beef (Semitendinosus muscle) was cooked in natural convection, forced convection and steam assisted hybrid oven and saturated steam oven at different oven temperatures until the geometric center of samples reached different end temperatures. Heterocyclic amine (HCA) compounds formation, soluble protein degradation kinetics, cook value, changes in fat content, surface colour and overall acceptance of cooked beef were determined. Soluble protein degradation of beef was considered as first order reaction kinetics and the reaction rate constants, k, were determined in the range of 0.014-0.052 min^?1. In steam assisted hybrid oven had higher reaction rate constants compared to that of the convection ovens. The effect of cooking temperature on soluble protein degradation for natural convection, forced convection and steam assisted hybrid oven followed the Arrhenius type of equation with activation energies of 12.45, 14.57 and 60.16 kJ/mol, respectively. Lower HCAs contents, shorter cooking times, lower cook values and lower fat retention were obtained by steam assisted hybrid oven cooking. Steam assisted hybrid cooking could be considered as an alternative cooking method to obtain a healthier product without compromising the eating habits of conventional methods due to better appearance (moderate burned surface) than saturated steam oven samples and a product retaining the most of the nutritional values.     

Baking kinetics of muffins in convection and steam assisted hybrid ovens (baking kinetics of muffin…)

Effects of oven type and baking temperature on acrylamide concentration, surface browning, temperature profiles and drying rates of muffins were investigated. Muffins were baked in convection and steam assisted hybrid ovens at 145, 160 and 175 °C for different baking times. For all oven types, the acrylamide concentration of muffins increased with increasing baking time and temperature (p < 0.05). The formation was considered as the first order reaction kinetics except for the lowest baking temperature at natural convection and steam assisted hybrid ovens. The reaction rate constant, k was found to be in the range of 0.027–0.078 (min⁻¹). For the forced convection oven, the effect of baking temperature on acrylamide concentration followed the Arrhenius type of equation; with activation energy of 36.35 kJ/mol. The minimum drying rate was observed by the steam assisted hybrid oven, at all conditions. Steam assisted baking resulted in lower acrylamide concentration at all baking temperatures, while providing the average moisture content not significantly different.     

Effect of Steam Baking on Acrylamide Formation and Browning Kinetics of Cookies

Abstract: Effects of baking method and temperature on surface browning and acrylamide concentration of cookies were investigated. Cookies were baked in natural and forced convection and steam‐assisted hybrid ovens at 165, 180, and 195 °C and at different times. For all oven types, the acrlyamide concentration and surface color of cookies increased with increasing baking temperature. Significant correlation was observed between acrylamide formation and browning index, BI, which was calculated from Hunter L, a, and b color values, and it showed that the BI may be considered as a reliable indicator of acrylamide concentration in cookies. Acrylamide formation and browning index in cookies were considered as the first‐order reaction kinetics and the reaction rate constants, k, were in the range of 0.023 to 0.077 (min^?1) and 0.019 to 0.063 (min^?1), respectively. The effect of baking temperature on surface color and acrylamide concentration followed the Arrhenius type of equation, with activation energies for acrylamide concentration as 6.87 to 27.84 kJ/mol; for BI value as 19.54 to 35.36 kJ/mol, for all oven types. Steam‐assisted baking resulted in lower acrylamide concentration at 165 °C baking temperature and lower surface color for all temperatures. Steam‐assisted baking is recommended as a healthy way of cooking providing the reduction of harmful compounds such as acrylamide for bakery goods, at a minimal level, while keeping the physical quality. Practical Application: The kinetics of acrylamide formation and browning of cookies will possibly allow definition of optimum baking temperatures and times at convectional and steam‐assisted baking ovens. The kinetic model can be used by developing baking programs that can automatically control especially a new home‐scale steam‐assisted hybrid oven producing healthy products, for the use of domestic consumers.     

Baking of muffins: Kinetics of crust color development and optimal baking time

Baking is a decisive stage in the production of bakery products, in general—muffins, in particular—for most of the quality attributes of the final products depend on it. The aim of this work is to model the kinetics of muffin crust color development during baking and to evaluate the feasibility of this kinetic model to predict the baking times. Surface color is represented by the Browning Index, and the effect of baking temperature (from 140 to 220 °C) and process convective characteristics (natural convection, forced convection, and steam-assisted forced convection) are analyzed. Minimal baking times are calculated from experimental core temperature measurements. The modeling of browning kinetics, which incorporates the optimal crust color determined by sensory analysis, allows the estimation of optimal baking times. For all the tested conditions t _op?>?t _min, assuring a product whose inner structure was already totally baked. Finally, minimal, half, and optimal baking times present an exponential dependence with the oven temperature. Besides, there are no significant differences between both forced convection modes.     

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 baking in different ovens on the quality and structural characteristics of saltine crackers

The aim of the study was to evaluate the physical and microstructural characteristics of crackers baked in four different industrial baking ovens (indirect radiation-cyclotherm, indirect convection, hybrid and industrial tunnel-ITO). Indirect convection and cyclotherm ovens provide the highest (5685.43 ± 51 W m⁻²) and the lowest (4860 ± 38.87 W m⁻²) amount of heat flux, respectively. Despite the amount of heat flux, indirect convection led to crackers with the highest moisture (7.86% vs. 4.82% in clyclotherm) and specific volume, but the lowest hardness. Cyclotherm resulted in crackers with lower specific volume, surface area, porosity, smooth and regular surface. Conversely, the hybrid and ITO ovens showed closer heat flux, leading to crackers with similar moisture content, texture parameters, specific volume, browning and inner porosity. Overall results show the potential of baking using different ovens for modifying the quality parameters of the crackers.     

PHYSICAL CHARACTERISTICS OF BEEF ROASTS PREPARED WITH DIFFERENT FOODSERVICE COOKING METHODS

Effects of cooking rate, fat trim level, aging period, endpoint temperature and oven type (conventional, forced air convection and forced air/steam combination) on yield, composition and cooking parameters for eight types of beef roasts were investigated. Generally, fast cooking, higher endpoint temperatures, complete removal of external fat and the use of forced air/steam combination ovens increased cooking losses. Fast cooking rates and forced air/steam combination ovens increased moisture loss in some roasts. Reduced levels of external fat did not dramatically affect yields or relative changes in composition due to cooking, but did increase cooking time per unit weight. Forced air/steam combination ovens may reduce the required length of preparation per unit raw weight while conventional ovens may increase cooking time. Rapid cooking of larger roasts with moist heat increased postcooking temperature rise. These results should aid in the revision of foodservice beef cookery guidelines.     

A quality comparison of breads baked by conventional versus nonconventional ovens: A review

Undesirable qualities of breads baked in nonconventional ovens have been observed by most researchers. The altered heat and mass transfer patterns and much shorter baking times associated with microwave radiation resulted in a crustless product with tougher, coarser, but less firm texture. Insufficient starch gelatinization, microwave-induced gluten changes, and rapidly generated gas and steam caused by the heating mode could be reasons for quality changes in the microwave-baked breads. Although breads baked in an electrical resistance oven did not brown, their interior characteristics and shelf-life were superior to those of products baked in a conventional oven. Bread with a superior keeping quality was obtained using an air impingement convection oven. The determination and explanation of the physical and biochemical changes that occur in products during baking in conventional versus nonconventional ovens are fruitful areas for future research.     

Kinetics of ascorbic acid degradation in potato blanching

Degradation kinetics of ascorbic acid was investigated on potato strips wrapped in aluminium foil and blanched for 5–60 min at different temperatures between 65°C and 100°C. The results confirmed that first order kinetics is adequate in describing the degradation reaction. The value of the rate constant was found to pass through a maximum at 85–90°C, indicating the inactivation of oxidative enzymes around these temperatures. Comparison of the degradation losses based on the present investigation with results on total loss of ascorbic acid during blanching reported in the literature showed that thermal degradation accounts for a considerable portion of the total loss.     

EFFECTS OF OVEN HUMIDITY ON FOODS BAKED IN GAS CONVECTION OVENS1

Bread, cakes, and cookies were baked in direct‐ and indirect‐gas fired, foodservice style convection ovens. Oven humidity was varied by including different numbers of perlite and water dummy loads during baking. Oven, product, and dummy temperatures were continuously recorded during baking, as was oven humidity. The properties of the finished baked foods were measured. Increased oven humidity resulted in products with higher yield, greater volume or spread, lighter color, and reduced firmness.     

Color Degradation Kinetics of Spinach, Mustard Leaves, and Mixed Puree

ABSTRACT: The kinetics of color degradation of spinach, mustard leaves, and mixed (mustard:spinach:fenugreek = 1:0.75:0.25) puree were investigated at temperatures between 75 and 115 °C. Color degradation was studied in respect to both visual green color (Hunter -a value) and total color [L × (-a) × b]. Degradation of color followed 1st-order reaction kinetics. Temperature dependence of the degradation rate constant obeyed the Arrhenius relationship with activation energies ranging between 19.71 and 41.64 kJ/mol. Higher activation energy value indicated greater temperature sensitivity of mustard leaves than spinach and mixed puree. Activation energies for visual green color were consistently higher than that for total color. Visual green color could therefore be used for on-line quality control of spinach, mustard leaves, and mixed puree during thermal processing.     

Processing of marjoram (Majorana hortensis Moench.) and rosemary (Rosmarinus officinalis L.). Effect of blanching methods on quality

Marjoram and rosemary are herbs which are valued for their flavour and colour. The use of microwave in blanching and drying is becoming more and more popular in recent years. This paper reports the effect of microwave blanching as compared to water and steam blanching on the volatile oil, colour, texture (by compression), chlorophyll and ascorbic acid contents of these herbs. There was maximum retention of ascorbic acid in microwave blanched marjoram and rosemary (21.5, 33.0 mg/100 g) i.e. 79.4% and 49.9% compared to fresh herbs. Blanching resulted in better retention of the original green colour of the fresh herb compared to direct drying of the herbs. Texture of microwave blanched herbs improved as revealed by higher compression force values (109.3, 157.8 N). However, there was greater loss of volatile oil in all the blanched samples.     

KINETICS OF HEAT/ENZYMIC DEGRADATION OF ASCORBIC ACID IN FLUTED PUMPKIN (Telfairia occidentalis) LEAVES

Thermal/enzymic degradations of ascorbic acid in whole, chopped and pureed fluted pumpkin leaves were studied from 60 to 100C (5–60 min). Degradation of ascorbic acid followed first order kinetics with the rate constants having maximum values at 80–90C. Ascorbic acid degradation exhibited strong deviation from linearity in thermal resistance, Arrhenius and absolute reaction rate plots at 100C indicating inactivation of the oxidative enzymes around 90C. At lower temperatures (60–90C) ascorbic acid was more stable in the whole and chopped leaves than in the pureed system. Activation energies ranged from 49 to 50.8 KJ mol⁻¹. At 100C, the puree matrix offered more protection to ascorbic acid.     

花色苷的热稳定性及其影响因素研究

花色苷是优良的天然植物源色素,同时具备抗氧化、抗肿瘤等重要生理功能。花色苷的热稳定性是影响其在食品工业中应用的主要因素,本文对花色苷的热降解动力学和热降解影响因素进行了综述。花色苷在食品中的热降解动力学均为一级动力学,影响其降解的主要因素包括pH、压强、温度、糖类、黄酮类物质、抗坏血酸类及其自身的酰基化程度。     

Baking of Sponge Cake: Experimental Characterization and Mathematical Modelling

Sponge cake is a sweet bakery product that begins as a fluid batter and, during baking, transforms into a porous solid, presenting an important volume expansion. The aim of this work was, first of all, to study experimentally the influence of operative conditions (natural and forced convection; oven temperature, from 140 to 180 °C; steam addition) on volume expansion and the heat transfer dynamics during baking of sponge cake. It was observed that an increase in oven temperature, airflow and steam injection produces an increase in volume expansion. Secondly, a mathematical model was developed to simulate heat transfer coupled with volume expansion. Both experimental and simulated temperature profiles verified that the last region to achieve a correct degree of baking is the one near the crust around the axial axis. In consequence, the minimal baking time was defined as the average time at which this region reaches 95–98 °C. The baking time was strongly affected by the effective oven temperature, with a slight influence of the convection mode.     

Physical and chemical changes in minimally processed green asparagus during cold-storage

The purpose of this research is to study effects of an innovative packaging method on the shelf-life of minimally processed green asparagus. The physical–chemical parameters analyzed (weight loss, colour, texture, chlorophyll and citric acid), and monitored by untrained panellists during the cold storage period at 6 °C, showed that pairing of a semi-permeable film with an adsorbent material and immersion in ascorbic acid solution were able to extend the shelf-life of green asparagus. Also, on the basis of the results obtained, a study of the chlorophyll and toughness degradation kinetics of green asparagus was conducted during cold storage. These data showed the toughening of asparagus spears to be faster than chlorophyll degradation. Thus, the former can be used as a reliable quality index to predict the shelf life of such products.     

Bakery product characteristics as influenced by convection heat flux

Energy consumption and product quality changes are often observed as the ratio of the convection to the conduction modes of heat transfer varies in industrial baking ovens. Air and oven-wall temperature profiles as well as air velocity can affect the convection/radiation heat transfer and hence the quality of the baked products. A programmable pilot-plant oven was used to establish five baking profiles by measuring the total heat flux and the convective component using a special heat flux meter called an h-monitor. The purpose was to keep the total heat flux delivered to the h-monitor constant while varying the convective component from 27% (for the standard profile) to 11%, 22%, 33% and 37% by modifying air characteristics and wall temperatures. Industrial cupcakes were baked using the five established baking profiles and then evaluated in terms of quality parameters. Compared to the standard profile, a 10% reduction in volume expansion and a 30% increase in texture properties were observed for extreme oven conditions; top colour was always darker but more uniform for the conditions with less convection. The moisture content of the middle part of the cake was always higher than that of the top, bottom and sides. Baking industries are interested in using the pilot-scale oven to modify baking profiles for the purposes of quality improvement, product development and energy savings, rather than having to engage in high-cost trial and error practices on the production site.     

Effects of Microwave, Steam and Water Blanching on Freeze-Dried Spinach

Microwave energy was demonstrated to be a convenient and effective method of blanching. Compared to steam or water, microwave blanching was superior in retention of ascorbic acid. The texture of rehydrated, microwave blanched spinach was firm, chewy and highly acceptable. Water blanching ruptured the cells and destroyed fine cellular structure as compared to steam blanching which caused less cellular disruption and greater retention of tissue structure. Microwave blanching resulted in coagulated protoplasmic material surrounding the cell walls. Cell and tissue structure remained intact which resulted in h gh rehydration ratios and acceptable textural characteristics. Microwave blanching yielded a superior freezedried product as compared to water and steam blanching.     

蒸汽辅助烤制技术 在肉类烹饪中的应用

随着蒸烤箱的快速发展,蒸汽辅助烤制技术被广泛应用在肉类食材加工中。蒸汽在高温烤箱中的引入改变了腔体中的传热状态,对食物质构特性产生复杂的影响,降低了烤肉的外观接受度,但具有减油减盐和减少有害物质产生的功能,可以提高肉品的健康性及安全性。因此,本文针对蒸汽辅助烤制的传热特性、对畜禽肉食用品质的影响以及蛋白氧化和杂环胺的生成等方面进行了详细的阐述。蒸汽辅助烤制作为一种新型加热技术,将对家庭烹饪和食品工业的发展产生重要作用。     

Pak Choi (Brassica rapa ssp Chinensis L) quality response to pre-harvest salinity and temperature

The effects of pre-harvest salinity levels (1.7, 9.5 and 12.3 mS cm⁻¹) and temperatures (18, 21 and 25 °C) on the ascorbic acid and total chlorophyll contents of Pak Choi (Brassica rapa ssp. Chinensis L) were investigated. The relationships of these chemical contents with storage period (0, 7 and 14 days) and water loss were also monitored. Increased production temperatures significantly (p < 0.001) reduced the ascorbic acid and total chlorophyll (p < 0.01). Ascorbic acid content in leaves grown at various salinities was significantly (p < 0.01) reduced beyond 9.5 mS cm⁻¹. Total chlorophyll was not affected by these different levels of salinity. Ascorbic acid contents of harvested shoots fell rapidly during the first seven days of storage, most markedly in shoots taken from plants grown at high salinity. The pattern of chlorophyll degradation depended on the plants' production environment where higher temperatures resulted subsequently in rapid degradation during storage. For shoots grown at high salinity, the chlorophyll content was sustained during early storage. Linear relationships were apparent between water loss and ascorbic acid and total chlorophyll contents of shoots from the range of treatments. © 1999 Society of Chemical Industry