Yazar "Ryu, Gi-Hyung" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim
    Öğe
    Effects of cold extrusion process on thiamine and riboflavin contents of fortified corn extrudates
    (Elsevier Sci Ltd, 2012) Boyacı, Berna Bilgi; Han, Jae-Yoon; Masatcıoğlu, M. Tuğrul; Yalçın, Erkan; Çelik, Süeda; Ryu, Gi-Hyung; Köksel, Hamit
    In this study, corn extrudates were produced from fortified corn flour by conventional and cold extrusion techniques at different barrel temperatures of 80, 110, 130 and 80 degrees C, respectively, and feed moisture contents. Thiamine and riboflavin contents of extrudates were determined by HPLC. Thiamine contents of the samples produced at feed moisture contents 20% and 25% decreased as temperature increased. There was no significant difference between riboflavin contents of conventional extrudates produced at both feed moistures at 80 and 110 degrees C barrel temperatures. However, riboflavin content of extrudates produced at 20% feed moisture was higher than the one produced at 25% feed moisture at 130 degrees C. In cold extrusion, there was no significant difference between riboflavin contents of samples. The samples produced by CO2 injection had the lowest expansion index and uniform air cells. However, the samples produced by conventional extrusion had higher expansion index and size distributions of air cells were not uniform. (C) 2011 Elsevier Ltd. All rights reserved.
  • Küçük Resim
    Öğe
    Hull-less barley flour supplemented corn extrudates produced by conventional extrusion and CO2 injection process
    (Elsevier Sci Ltd, 2014) Masatcıoğlu, Mustafa Tuğrul; Yalçın, Erkan; Hwan, Park Jong; Ryu, Gi-Hyung; Çelik, Sueda
    The effects of feed moisture content (20, 25%), exit-die temperature (80, 130 degrees C), and extrusion-cooking method (with/without CO2 injection) on beta-glucan (BG) levels and physicochemical properties of hull-less barley flour (HBF) supplemented (15, 30, 45%) corn extrudates were investigated. The highest HBF supplementation level (45%) resulted in higher BG levels (2.87-3.28%) in all extrusion conditions. In general, increasing feed moisture content from 20 to 25% and exit-die temperature from 80 to 130 degrees C resulted in small increases in enzyme resistant starch type-3 (RS3) levels. However, the investigated extrusion conditions did not form substantial amount of RS3 and the highest RS3 content was 540 mg/100 g. Lower feed moisture content and higher exit-die temperature resulted in higher water solubility (WS) and lower water-binding capacity (WBC) values. Cold-paste viscosity (CV) was observed in all extrudates. High WS and WBC values of extrudates and the existence of CV values in RVA curves indicated complete starch gelatinization. Industrial relevance: CO2 injection has been proved as a reliable alternative method to the conventional extrusion process used in the breakfast cereals and snack food industry. The overall quality of the product processed by CO2 injection was comparable to that of the current process. The extrudates produced by CO2 injection method had more uniform expansion and smoother surface. CO2 injection did not have a reducing effect on beta-glucan levels; however, it is expected to result in a better retention of heat labile micronutrients and hence more healthy food products. (C) 2014 Elsevier Ltd. All rights reserved.
  • Küçük Resim
    Öğe
    Physical and chemical properties of tomato, green tea, and ginseng-supplemented corn extrudates produced by conventional extrusion and CO2 injection process
    (Springer, 2013) Masatçıoğlu, M. Tuğrul; Yalçın, Erkan; Kim, Mihwan; Ryu, Gi-Hyung; Çelik, Sueda; Köksel, Hamit
    In this study, extrudates were produced from corn flour supplemented with tomato, green tea, and ginseng powder by conventional extrusion and CO2 injection methods. In conventional extrusion process, the die exit temperatures were adjusted to 80, 110, 130 A degrees C and CO2 injection method was carried out at 80 A degrees C. In both extrusion methods, the feed moisture, screw speed, and die diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Corn flour was supplemented with tomato powder at three different levels (4, 8, and 12 %), but ginseng and green tea were added only at 8 % level. The bulk density results generally had an inverse relationship with the expansion index values. Higher tomato powder supplementation levels resulted in higher total phenolic compound levels and antioxidant activities. These increases were around 11-fold as compared to control samples in 12 % tomato powder supplementation level at 130 A degrees C extrusion temperature. The results indicated that antioxidant activity increased with increasing extrusion temperature. This increase might be due to higher amount of Maillard reaction products, with antioxidant activity, formed at higher extrusion temperatures. The color (L*, a*, b*) and hydroxymethylfurfural results proved that the rate of Maillard reaction increased at higher extrusion temperatures during the extrusion process. Green tea supplementation resulted in higher total phenolic compounds and antioxidant activity values as compared to tomato and ginseng supplementation under the same extrusion conditions.