SCREW CONFIGURATION EFFECTS ON STARCH BREAKDOWN DURING TWIN-SCREW EXTRUSION of RICE FLOUR

Extrusion cooking, as a multi-step, multi-functional and thermal/mechanical process, has permitted a large number of food applications. Effects of extrusion cooking on nutritional quality are ambiguous. Beneficial effects include destruction of antinutritional factors, gelatinisation of starch, increased soluble dietary fibre and reduction of lipid oxidation. On the other hand, Maillard reactions between protein and sugars reduce the nutritional value of the protein, depending on the raw material types, their composition and process conditions. Heat-labile vitamins may be lost to varying extents. Changes in proteins and amino acid profile, carbohydrates, dietary fibre, vitamins, mineral content and some non-nutrient healthful components of food may be either beneficial or deleterious. The present paper reviews the mechanisms underlying these changes, as well as the influence of process variables and feed characteristics. Mild extrusion conditions (high moisture content, low residence time, low temperature) improve the nutritional quality, while high extrusion temperatures (P200°C), low moisture contents (<15%) and/or improper formulation (e.g. presence of high-reactive sugars) can impair nutritional quality adversely. To obtain a nutritionally balanced extruded product, careful control of process parameters is essential.

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“…, 1994b). Screw configuration can be designed to minimise or maximise starch breakdown (Gautam & Choudhoury, 1999).…”

Section: Nutritional Changesmentioning

confidence: 99%

Nutritional aspects of food extrusion: a review

Singh

Gamlath

Wakeling

2007

Int J of Food Sci Tech

648

489

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“…The arrangement of different pitches, lengths, stagger angles, positions and spacings define a screw configuration, which is a main factor influencing the extent of mixing, product transportation, extrudate properties, mechanical energy input and residence time distribution during extrusion processing [24,25,26,27]. With different screw configurations, the twin screw extruder can conduct diverse functions and processes in a single step, such as material transporting, heating, mixing, shearing, grinding, chemical reaction, drying and liquid-solid separation [28].…”

Section: Pretreatment Of Lignocellulosic Biomassmentioning

confidence: 99%

Extrusion Pretreatment of Lignocellulosic Biomass: A Review

Zheng

Rehmann

2014

IJMS

163

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Bioconversion of lignocellulosic biomass to bioethanol has shown environmental, economic and energetic advantages in comparison to bioethanol produced from sugar or starch. However, the pretreatment process for increasing the enzymatic accessibility and improving the digestibility of cellulose is hindered by many physical-chemical, structural and compositional factors, which make these materials difficult to be used as feedstocks for ethanol production. A wide range of pretreatment methods has been developed to alter or remove structural and compositional impediments to (enzymatic) hydrolysis over the last few decades; however, only a few of them can be used at commercial scale due to economic feasibility. This paper will give an overview of extrusion pretreatment for bioethanol production with a special focus on twin-screw extruders. An economic assessment of this pretreatment is also discussed to determine its feasibility for future industrial cellulosic ethanol plant designs.

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“…The detailed method is presented by Gautam (1998). The technique employs the Archimedes principle of fluid displacement to determine volume.…”

Section: Densitiesmentioning

confidence: 99%

Hydrolyzed Fish Muscle as a Modifier of Rice Flour Extrudate Characteristics

Choudhury

Gautam

2003

Journal of Food Science

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The effects of fish protein hydrolysis time and fish solids level on macroscopic properties of extrudates were investigated. Arrowtooth flounder muscle was autolyzed for varying times; hydrolyzed muscle was recovered, dried, blended with rice flour at varying levels, and extruded using a twin-screw extruder. Hydrolysis beyond 5 min had little effect on extrudate properties. Addition of hydrolyzed fish solids strikingly decreased the apparent density and breaking strength but increased extrudate porosity and expansion ratios. In general, the effect was greater when the level of fish solids was higher. Opposite and expected trends were observed for blends with unhydrolyzed fish solids. Fish solids level played a dominant role in increasing true density.

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SCREW CONFIGURATION EFFECTS ON STARCH BREAKDOWN DURING TWIN-SCREW EXTRUSION of RICE FLOUR

Cited by 36 publications

References 18 publications

Nutritional aspects of food extrusion: a review

Nutritional aspects of food extrusion: a review

Extrusion Pretreatment of Lignocellulosic Biomass: A Review

Hydrolyzed Fish Muscle as a Modifier of Rice Flour Extrudate Characteristics

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