Hilal Isleroglu

Effect of steam baking on acrylamide formation and browning kinetics of cookies.

UNLABELLED 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.

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.

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.

EFFECT OF SPRAY-FREEZE DRYING PROCESS ON PHYSICAL PROPERTIES OF MALTODEXTRIN

In this study, to determine the effect of spray-freeze drying (SFD) on physical properties of maltodextrin such as moisture content, water activity, color, bulk and particle properties, maltodextrin solutions were sprayed into liquid nitrogen using ultrasonic nozzle (48 kHz) with a constant flow rate (8 ml/min) and the frozen samples were dried at different shelf temperatures (2545°C) and different drying times (6-16 hours). The effects of SFD on physical properties of the powder were investigated statistically using response surface-contour graphs and ANOVA. As a result, the effects of SFD conditions on moisture, b value, bulk density, tapped density and flowability have been determined significant, statistically. Drying time was significant for the L and a values, and dispersibility; however, the effect of shelf temperature was significant for the particle density and porosity, statistically. Furthermore, the particles in spherical shape and having uniformly distributed pores on the surface were obtained.

PÜSKÜRTMELİ-DONDURARAK KURUTMA İŞLEMİNİN MALTODEKSTRİNİN FİZİKSEL ÖZELLİKLERİ ÜZERİNE ETKİSİ

Bu calismada puskurtmeli-dondurarak kurutma (PDK) isleminin maltodekstrinin nem icerigi, su aktivitesi, renk, yigin ve partikul ozellikleri uzerine etkisinin belirlenmesi amaciyla maltodekstrin cozeltisi ultrasonik nozul (48 kHz) kullanilarak, sabit bir besleme debisi ile (8 ml/dak) sivi azot uzerine puskurtulmus ve dondurulan ornekler farkli plaka sicakligi (25-45oC) ve kurutma surelerinde (6-16 saat) kurutulmustur. PDK isleminde kurutma kosullarinin toz urunun fiziksel ozellikleri uzerine etkisi istatistiksel olarak yanit yuzey-kontur grafikleri ve ANOVA analizi ile saptanmistir. Sonuc olarak, PDK islem kosullarinin nem icerigi, b degeri, yigin ve sikistirilmis yogunluk ile akabilirlik uzerine istatistiksel olarak anlamli bir etkisinin oldugu belirlenmistir. L ve a degerleri ile dagilabilirlik uzerine sadece kurutma suresinin, partikul yogunlugu ve porozite uzerine ise sadece plaka sicakliginin etkisinin istatistiksel olarak anlamli oldugu tespit edilmistir. Ayrica, PDK islemi ile kuresel ve yuzeyinde duzgun dagilimli porlar bulunan partikuller elde edilmistir.

Kinetics of colour, chlorophyll, and ascorbic acid content in spinach baked in different types of oven

ABSTRACT Spinach was baked in steam-assisted hybrid ovens, natural and forced convection ovens, and saturated steam ovens at different temperatures and baking times. The moisture content, water activity, peroxidise activity, colour, ascorbic acid, and chlorophyll content were determined for each baking time and kinetic analysis of thermal degradation of the colour, chlorophyll, and ascorbic acid were evaluated. Degradation of green colour, total chlorophyll, and ascorbic acid in spinach leaves during the baking process was considered as first order reaction kinetics and temperature dependency of degradation was described by the Arrhenius equation. Baking in steam-assisted hybrid ovens resulted in the highest rate of reaction for both colour change and chlorophyll degradation, followed by forced convection and then natural convection ovens. The existence of steam in the baking chamber resulted in an acceleration of the baking process and better ascorbic acid retention in spinach was determined by baking in steam-assisted hybrid ovens. Degradation kinetics could allow definition of optimum baking temperatures and times in different types of ovens and shorter baking times should be preferred in steam-assisted hybrid ovens if fresh appearance (high greenness) is desired.

Effect of oven cooking method on formation of heterocyclic amines and quality characteristics of chicken patties: Steam-assisted hybrid oven versus convection ovens

The aim of this study was to evaluate effect of steam-assisted hybrid oven cooking method in comparison with convection ovens (natural and forced) on quality characteristics (color, hardness, cooking loss, soluble protein content, fat retention, and formation of heterocyclic aromatic amines) of chicken patties. The cooking experiments of chicken patties (n = 648) were conducted at oven temperatures of 180, 210, and 240°C until 3 different end point temperatures (75, 90, and 100°C) were reached. Steam-assisted hybrid oven cooking enabled faster cooking than convection ovens and resulted in chicken patties having lower a* and higher L* value, lower hardness, lower fat, and soluble protein content (P < 0.05), and higher cooking loss than convection ovens. Steam-assisted hybrid oven could reduce the formation of heterocyclic aromatic amines that have mutagenic and carcinogenic effects on humans.