有機酸、脂肪酸、磷酸鹽和鹼對米穀粉糊化性質之影響

Effects of organic acids, fatty acids, phosphates, and alkalis on the pasting properties of rice flour from waxy and non-waxy varieties

鄔文盛(Wen-Sheng Wu)

指導教授 ： 黃卓治

國立屏東科技大學/農學院/食品科學系所/博士(2009年)

https://doi.org/10.6346/NPUST.2009.00113

摘要

本論文研究目的在探討添加有機酸、脂肪酸、磷酸鹽和鹼對米穀粉糊化性質之影響，以改善米食加工品糊化性質和質地特性。以台秈2號米和台秈糯2號米為原料米 (2004年一期作)，分別添加0.1 mM、1 mM和10 mM有機酸包括醋酸、乳酸、蘋果酸、琥珀酸和檸檬酸，添加量分別為0.5和 2.0 % (v/w，米穀粉乾重為基準) 於米穀粉中，利用快速黏度測定儀 (RVA) 測定米穀粉糊化黏度，米穀粉凝膠則以TA-XT2i質地分析儀來進行質地剖面分析 (TPA)。結果發現，添加0.1 mM有機酸後使台秈2號米米穀粉尖峰黏度、熱糊黏度、最終黏度和回升黏度明顯 (p<0.05) 下降，而凝膠硬度和控制組比較時明顯(p<0.05) 減少。顯示添加0.1 mM有機酸能夠延緩此種米穀粉冷藏時的老化趨勢，延緩質地回凝、變硬的現象，並改善冷藏安定性。至於台秈糯2號米，添加1 mM有機酸會明顯 (p<0.05) 使其糊化黏度指標下降，但是添加0.1 mM或 10 mM有機酸，則沒有這種趨勢；同時添加有機酸後，其質地方面和控制組比較時大部份沒有明顯差異。
分別添加脂肪酸包括肉豆蔻酸、棕櫚酸和硬脂酸，添加量分別為1.5、3.0和 4.5 % (w/w，米穀粉乾重為基準) 於台秈2號米 (2005年和2006年一期作)之米穀粉中，同樣利用快速黏度測定儀 (RVA) 測定黏度。結果發現添加脂肪酸後，都會使台秈2號米米穀粉糊化性質明顯 (p<0.05) 改變，添加棕櫚酸時，尖峰黏度和破裂黏度明顯 (p<0.05) 低於控組，而最終黏度和回升黏度則有明顯 (p<0.05) 上升的現象。
分別添加三種不同磷酸鹽包括磷酸氫二鈉SPD，重合磷酸鹽STP 和三偏磷酸鈉STMP添加量分別為0.1、0.2和0.5 % (w/w，米穀粉乾重為基準)於台秈2號米和台秈糯2號米 (2005年一期作)之米穀粉中， 對台秈2號米之糊化性質的影響除破裂黏度外，其餘糊化性質均明顯(p<0.05)下降；同時造成硬度和附著性 (adhesiveness) 明顯 (p<0.05)下降，顯示添加磷酸鹽能夠延緩此種米穀粉在冷藏時的老化趨勢。台秈糯2號米 (2005年一期作)之米穀粉則在添加磷酸鹽後糊化黏度明顯 (p<0.05) 下降，質地也隨之改變。
台秈2號米和台秈糯2號米 (2005年一期作) 之糊化性質亦會隨著添加不同的鹼 (硼砂和碳酸鈉)，添加量分別為0.1、0.2 和0.5 %以及0.5、1.0和2.0 % (w/w，米穀粉乾重為基準) 而有明顯的 (p<0.05) 差異，當添加量同在0.5 %時，結果顯示添加硼砂之糊化黏度明顯高於碳酸鈉。而台秈2號米穀粉凝膠硬度、附著性明顯 (p<0.05) 低於控制組。
添加有機酸和磷酸鹽將有助於改善將台秈2號米穀粉應用在中式傳統米食加工品等在冷藏時質地回凝、變硬的現象，並且改善產品的冷藏安定性，提供使用有機酸、脂肪酸、磷酸鹽和鹼，以改善米食加工品的糊化性質、風味和質地的方法。

關鍵字

有機酸、脂肪酸、磷酸鹽、鹼、米穀粉、糊化性質、質地剖面分析

並列摘要

The objective of this study was to investigate the effects of organic acids, fatty acids, phosphates, and alkaline on the pasting properties of rice flours in order to improve the pasting and textural properties of rice products. Taisen number 2 (TS2) and Taisen waxy number 2 (TSW2) (first crop of 2004) were selected as rice material. Organic acids including acetic acid, lactic acid, malic acid, succinic acid, and citric acid of 0.1 mM, 1 mM and 10 mM were added to the rice flour (v/w, on dry basis) at 0.5 and 2.0 % levels and cooked in Rapid Visco Analyser (RVA) at 95℃ for 12.5 minutes. The resulting gel texture profile analysis (TPA) from RVA was carried out on a texture analyzer. Results showed that the effects of organic acids on the pasting and textural properties were different. Addition of 0.1 mM organic acids significantly (p<0.05) decreased final viscosity and setback of TS2 rice flour. The hardness and adhesiveness of rice flour gel were significantly (p<0.05) decreased by the addition of organic acids compared to the control. Reduced final viscosity exhibited that the addition of organic acids were able to retard the tendency of rice flour to retrograde. Indicative that the addition of organic acids was able to retard the tendency of this rice flour to retrograde even at 4℃ at which temperature the tests were performed. Waxy rice flour, TSW2, showed significantly (p<0.05) decreases in overall pasting viscosities by addition of 1 mM organic acids, but not the same tendency at addition of 0.1 mM and 10 mM organic acids. Most of the textural properties were not significantly different compared to the control.
Fatty acids including myristic acid, palmitic acid, and stearic acid were added to the rice flour (w/w, on dry basis) at 1.5, 3.0 and 4.5 % levels and cooked in Rapid Visco Analyser (RVA) at 95℃ for 12.5 minutes. Results showed that addition of the fatty acids significantly (p<0.05) changed rice flour pasting properties relative to the native flour, regardless of the rice harvested in 2005 or 2006. Addition of myristic acid or palmitic acid could significantly (p<0.05) decrease peak viscosity, breakdown, and increase final viscosity and setback of the rice flour compared to those of the control. While the levels of palmitic acid increased, the peak viscosity and breakdown of rice flour decreased. However, final viscosity and setback of rice flour increased.
The effects of addition of the three phosphates including sodium phosphate dibasic (SPD), sodium tripolyphosphate (STP), and sodium trimetaphosphate (STMP) at 0.1, 0.2, and 0.5 % (w/w, on dry basis) on the pasting properties of the non-waxy TS2 rice flour were different. Addition of phosphates significantly (p<0.05) reduced hardness and adhesiveness of the non-waxy rice flour gel compared to those of the control. For waxy rice flour, TSW2, showed significant (p<0.05) decreases in all viscosity parameters compared to the control due to addition of phosphates. The texture of waxy and non-waxy rice flour gel was different with addition of phosphates.
Effects of alkalis on the pasting properties of the rice flours revealed that the pasting properties of the two rice flours (harvested in 2005) were significantly (p<0.05) different with addition of the 2 alkalis including sodium borate and sodium carbonate at 0.1, 0.2, and 0.5 % and 0.5, 1.0 and 2.0 % (w/w, on dry basis) respectively. Sodium borate seemed to affect the pasting properties of the two rice flour more pronounced than sodium carbonate at the same level of addition 0.5% ( on dry basis of rice flour). Hardness and adhesiveness of the non-waxy rice flour were significantly (p<0.05) decreased with addition of sodium borate and sodium carbonate compared to those of the control.
The non-waxy rice flour with addition of organic acids and phosphates could be used for Chinese traditional rice products to reduce the susceptibility to syneresis or retrogradation and to improve the stability of rice products during low-temperature storage. In addition, this study leads to use of organic acids, fatty acids, phosphates, and alkalis to modify the viscosity and texture of rice products.

並列關鍵字

Organic acids ； Fatty acids ； Phosphates ； Alkalis ； Rice flour ； Pasting properties ； Texture profile analysis (TPA)

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