無麩質全榖物西式米麵條之研發

Abstract

以全穀物利用之概念，選用國產稻米、苦蕎及黃豆為主原料，開發三種適合冷凍貯藏運送之類西式米麵條產品(pasta-like rice product)，其分別為糙米麵、多榖麵 (糙米-苦蕎)及穀豆麵(糙米-黃豆)。試驗中，探討原料種類、原料粉規格、雙軸擠壓製程中進料水量（30、40及50 %）及螺軸轉速（300及500 rpm）對西式米麵條產品之製作與品質影響，並且針對特定機能性成分進行分析，探討擠壓製程及原料性質對特定機能性成分之影響。試驗結果發現，粉料平均粒徑小於150μm及破損澱粉含量介於16-26%，有助於提高澱粉糊化程度，另外，適當直鏈澱粉(24-26 %)含量有助麵條回凝成形並且與適口性有關。多榖麵中，所使用之30 %帶殼苦蕎粉，含有纖維粒徑小於10 μm者，因保水性佳可降低煮麵損失率及提高麵條最大截切力。在高螺軸轉速及低加水量時，由於擠壓套筒末端內壓驟升，致使麵條有部分膨發現象，導致產品外觀及煮麵品質不佳。擠壓時，最適進料水量主要決定於原料粉之性質，但由煮麵性質測定結果發現加水量改變對煮麵損失率之影響顯著大於螺軸轉速的差異，而熟麵條之最大截切力與烹煮損失率則呈負相關性。擠壓時，以相同加水量製作之麵條，其糊液黏度測定結果顯示，回凝黏度值隨著螺軸轉速提高而下降，推測在高螺軸轉速下，剪切力提高，發生澱粉降解現象。在麵條機能性成分分析方面，體外消化試驗結果顯示，榖物原料中含有7-11%之抗解澱粉，而擠壓麵條亦有3-10%抗解澱粉，但由熱性質分析結果得知，擠壓麵條中主要為第三型抗解澱粉。慢速水解澱粉及抗解澱粉對於升糖指數(estimated glycermic index, eGI)有高度負相關性。另外，由於多穀麵(糙米-苦蕎)中含有15%之帶殼苦蕎粉，其eGI顯著低於其他兩種麵條；經過擠壓蒸煮過程，麵條之總酚化合物、維生素E及米糠醇含量有下降趨勢。多榖麵(糙米-苦蕎)中蘆丁含量豐富，且經擠壓過程蘆丁受酵素作用轉化為槲皮素，使得抗氧化能力提高。本試驗所開發的三種全穀物類西式米麵條富含膳食纖維(2.6-6.4%)，為日常膳食之良好來源。

The objective of this study was to establish the technique to produce whole grain non-gluten pasta-like products made with the domestic grown grains and legumes by using a twin-screw extruder. Three major whole grain pasta-like rice products (PLP) were developed, which are whole rice (brown rice), whole multigrain (brown rice and tartary buckwheat) and whole grain and bean (brown rice and soybean). In this study, the factors affecting the quality of whole grain products include the type of raw materials, the specification of flours, feed moisture (30, 40 and 50%) and screw speed (300 and 500 rpm) during extrusion processing. The specific bioactive compounds (including resistant starch, Vit E, γ-oryzanol and rutin) were analyzed. The results show that the particle size of grain flour should be less than 155 μm, the damaged starch content should be within 16-30% and the amylose content of flours should be 24-26% for good quality of whole grain PLP. It's worth noting that small particle size of tartary buckwheat fiber (<10 μm) could reduce the cooking loss and increase the maximum cutting force of whole multigrain PLP. Slightly puffing could be occurred when the noodle was extruded at high pressure resulting from the high screw speed and low feeding water. The appropriate amount of the feeding water of extrusion was depending or the flour properties, which has a greater impact on the extrusion than the screw speed. The maximum cutting force of cooked pasta was negatively correlated with the rate of cooking loos. As the same feeding water applied, a decrease of setback viscosity could be found when high screw speed was applied to make whole grain PLP. This is attributed the starch degradation under high shearing. The resistant starch content of raw flours and whole grain PLP were 7-11% and 3-10 %, respectively. The results of DSC show that resistant starch in whole grain PLP was type III. The amount of slowly digestible starch and resistant starch was positively correlated with eGI. The whole multigrain pasta-like noodle had the lowest eGI than others, attributing to the 30% of hulled tartary buckwheat flour were included. The extrusion had infurior effect on the bioactive compouds, such as total phenolics, Vitamin E and γ-oryzanol. Moreover, rutin was bioconverted into quercetin by rutin degradation enzyme during extrusion process, resulting bitter flavor of whole multigrain PLP. The whole grain pasta-like products developed in this study, containing high dietary fiber content, low sodium content and having good palatability, have great potential and competition in the food market.