Color Of Extrudates Research Articles

Textural and Sensory Characteristics of Milk Protein- Maize Flour-based Extrudates

Sensory and textural characteristics of milk protein-maize-based extrudates were studied as affected by extrusion conditions and milk-proteins Rennet Casein (RC), skimmed milk powder (SMP) and whey protein concentrate (WPC) to maize ratio. Appearance attributes of products decreased significantly (P<0.05) with SMP addition and higher feed moisture content, but improved with WPC-70 and RC. Colour of extrudates was mostly affected by the milk protein- maize ratios, especially with increase in SMP concentration that led to significantly (P<0.05) darker products scoring less than five due to the presence of higher amount of lactose. Feed moisture content decreased mean sensory score for crispness and increased hardness of the extrudates. Overall acceptability of extrudates decreased with the addition of SMP and increase in feed moisture content, except in WPC-70 at 8% level of protein. Extrudate with 8% RC and 12% feed moisture treated at 40 0 C inlet and 100 0 C outlet cooking zone temperature at screw speed of 340 rpm gave minimum maillard browning, desired textural characteristics, and colour. The correlation of sensory and textural properties showed that textural characteristics can be related with appearance which affected the product most.

Influence of dried Hokkaido pumpkin and ascorbic acid addition on chemical properties and colour of corn extrudates

The influence of Hokkaido pumpkin powder (PP) addition to corn grits at levels 4%, 6%, and 8% and ascorbic acid (AA) addition at levels 0.5% and 1% was evaluated. Extrusion was done using a single-screw extruder at two temperature regimes: 135/170/170°C (E1) and 100/150/150°C (E2). Mathematical models that describe the influence of additives on the colour of extrudates were determined. Raw extrusion mixtures as well as obtained extrudates were tested for ascorbic acid, polyphenol, proteins, fat, crude fibre, ash and carotenoids content, and antioxidant activity. E1 extrusion regime acted favourably on polyphenols, crude fibre content, and antioxidant activity. It also caused higher fat degradation than E2 extrusion. Xanthophylls (lutein and zeaxanthin) were less sensitive to extrusion than carotenes (α-carotene, 9-cis-β-carotene and 13-cis-β-carotene). Ascorbic acid was more sensitive to higher extrusion temperatures (49–76% degradation). It provided protection to carotenoids and consequently the colour of the extrudates.

SENSORY PROPERTIES AND ACCEPTABILITY OF CORN AND LENTIL EXTRUDED PUFFS

ABSTRACT Sensory characteristics of corn and corn–lentil extrudates were investigated as affected by extrusion conditions and legume-to-corn ratio. Appearance attributes of products were decreased with extrusion temperature and feed moisture content, but improved with feed rate. Color of extrudates was mostly affected by the lentil-to-corn ratio so that its increase led to darker products. Extrusion temperature improved crispness and melting of extrudates. Feed moisture content decreased crunchiness and crispness of the extrudates and increased hardness. Overall acceptability of extrudates generally decreased with the addition of lentil flour (except for 30% material ratio) and the increase in feed moisture content and temperature. The correlation of sensory properties showed that textural characteristics can be related with appearance and flavor attributes. Manipulation of the process conditions during extrusion can lead to preparation of products with desired sensory attributes. PRACTICAL APPLICATIONS Sensory characteristics of corn and corn–lentil extrudates developed in this study could be used by the snack industry to understand the similarities and differences of extruded snacks produced at different extrusion conditions and feed compositions and to select the appropriate ranges of processing conditions to meet consumers' expectations. This study suggests that acceptable snacks can be produced even at high legume contents if the process conditions are selected properly.

Assessment of color development due to twin-screw extrusion of rice–glucose–lysine blend using image analysis

An image analysis method was developed to determine the color change of rice–glucose–lysine blend during extrusion. The color of extrudates was analysed and compared by using different extrusion conditions. Extrusion process variables included moisture content, screw speed, barrel temperature, and screw geometry. The influence of specific mechanical energy input (SME) and product temperature on the color of extrudates was significant. The color parameters were related to product temperature and SME by a 4th degree polynomial. Product temperature and color were modeled and tested using rice–glucose–lysine blend at various screw configurations and extrusion conditions with reasonable accuracy. Validations of product temperature and color models were done using different screw geometries and other processing variables with reasonable accuracy. Extrusion tests indicated that the developed predictive models can be of use for extrusion processing. The results also showed that the image analysis method developed provides an objective and efficient approach for assessing the color development of extrudates.

Modelling the effects of peanut flour, feed moisture content, and extrusion temperature on physical properties of an extruded snack product

SummaryA mixture experimental design was used to evaluate the combined effects of non‐fermented (PDPF) and fermented (F‐PDPF) peanut flours, added feed moisture content, and extrusion temperature on physical properties of extruded cornstarch‐peanut flour‐based snacks. Moisture content, expansion ratio, bulk density, modified Kramer compression‐shear force and colour of extrudates were significantly affected by the amount of PDPF and F‐PDPF in the formulation. Oil absorption by extrudates was only influenced by the type of peanut flour. Within the range of (per 1‐kg batch) 0.30–0.34 g g−1 added water, 0.16–0.20 g g−1 PDPF and/or F‐PDPF, and extrusion temperatures of 125 to 150°C, extrudates with a wide range of functional characteristics can be produced.

Feed Moisture Effects on Functional Properties, Trypsin Inhibitor and Hemagglutinating Activities of Extruded Bean High Starch Fractions

ABSTRACTHigh starch fractions (HSF) of navy, pinto and garbanzo beans were extruded with different moisture contents using a Wenger X‐5 extruder. Increasing moisture content resulted in increased expansion index for navy and garbanzo beans and a decrease for pinto bean. The highest water absorption index was obtained for navy bean HSF at moisture 27%, for pinto 30% and for garbanzo 26%. For all beans, water solubility index decreased with increasing moisture. Color of extrudates also was affected by moisture. The extrusion process reduced trypsin inhibitor activity by about 70–85%, the level of decrease determined by moisture content of starting material and temperature. Extrusion temperatures of 121, 132 and 150°C inactivated hemagglutinating activity of navy, pinto and garbanzo beans.