Effect of Ions on the Heat Reversible Characteristics of Hsian-tsao gel

Abstract

為探討仙草多糖膠質在凝膠後的加熱再溶解現象，本研究利用不同濃度之鋰、鈉、鉀、銨根一價離子與鎂、鈣、鋇二價離子溶液，浸泡0.8cm3之仙草凝膠顆粒或將離子直接加入仙草萃取液中，再添加澱粉讓其凝膠，測定100℃、60分鐘及121℃、15分鐘下殘存仙草膠體顆粒之凝膠強度，結果顯示浸泡高濃度之一價或二價離子，皆可抑制凝膠顆粒熱溶現象及增強凝膠強度。不同離子種類抑制膠溶現象之效果以鈣離子最佳，其濃度愈高則凝膠強度也愈高。仙草萃取液直接添加離子之效應，顯示鋰、鈉離子濃度大於800ppm、2,000ppm，鉀、鉚及銨根離子在3,000ppm以上時，都會明顯抑制仙草凝膠現象之形成。而鈹、鎂、鈣、鋸、鋇離子之濃度分別在40、60、60、100、100ppm以上時，也會抑制仙草凝膠作用之發生。仙草之萃取及製罐，必需注意萃取用水之品質及碳酸鈉之用量。以0.04~0.06％氯化鈣溶液處理仙草凝膠顆粒，則可防止仙草凝膠之高溫溶解現象。 Dissolve of hsian-tsao gel subjected to heat treatments were examined. Hsiantsao gel in 0.8 cubic centimeter were dipped into the lithium, sodium, potassium, ammonium,calcjum, magnesium, and barium chloride solutions at the concention ranged from 0.02 to 2.0%, respectively, and thos metal ions were also added directly to the 1.2oBrix diluted hsian-tsao extract,those gel strength were measured then after wheat starch were added and gelatinized under 100 ℃ ,60 minutes and 121 ℃ ,15 minutes boiling. The results indicated that dipping in high concentration of cation solution not only inhibited the gel dissolution occurrence but also increased the gel strength of hsian-tsao. Calcium cation was the most effectively reagent to inhibit the gel dissolution among those ion treatments. Direct addition of cation to the diluted hisan-tsao extract showed the inhibition of gel formation when lithium, sodium ion concentration were above 800, 2,000 ppm,respectively, and the potassium, rubidium, ammonium ion were above 3,000 ppm. The same effect of alkali earth metal ion on gel formation was also noted when the concentration for beryllium, magnesium, calcium, strontium, and barium ion were above 40,60,60,100,100 ppm,respectively. Thus, during the extraction and canning, precaution should be taken to the water quality and dosage of sodium carbonate. In addition, in order to prevent the gel dissolution, 0.04 % to 0.06 % calcium chlorides solution could be applied