Study of Persimmon Dehydration Using Dehumidification Method

本省柿餅製造多在陽光下吹風晾乾，其製程曠廢時日，若受陰雨氣候影響，常有30至70％腐爛率，對果農損失極大，以烘乾機製造柿餅，則有厚皮且脫澀不完全現象。為解決柿餅製造過程中因雨導致之大量腐敗，並製造出優良品質之柿餅，本研究將總量935公斤之柿青，分四批先後逐日置於控制溫濕度之乾燥室中（28-30.5℃、RH 48.3-69.8%)，約經過5個單元循環操作（每個循環為除濕18小時，停機6小時）可以製成柿餅，其較自然日曬法約快兩天。除濕乾燥室中之除濕機除濕能力不足時，會導致乾燥室中濕度上升，隨後發生腐爛，此現象出現在柿青進行乾燥之第三或第四天，即柿子果實開始成熟軟化時。以除濕乾燥法製造柿餅，可以得到與日曬乾燥法所製相同之柿餅色澤，且其色澤呈現均一誘人之金黃色。果糖、葡萄糖為柿餅中主要之糖類，其在乾燥過程中因水分份蒸發而濃度增加，其中又以自然日曬法者較高。柿餅之硬度在除濕乾燥四天後達到最高之530克，自然日曬法製得之柿餅則在乾燥約七天後才達到相同之硬度。柿餅乾燥過程中水活性持續下降，但仍未達常溫下可以保存之程度。 Dehydration of persimmons (Diospyros kaki L.) using dehumidification method at the range from 30℃ to 35℃ and 50 to 65% relative humidity environment resulted in the highest yield and the best quality of dehydrated persimmons, as compared to the products made from conventional sun drying method. Dehumidification of persimmons at above conditions for 18 hours and then turn off the dehumidifier for six hours was the best operation condition for persimmon moisture balance and case hardening prevention. The dehumidification process took five days to remove about 61.3 % moisture of the persimmon. It is two days shorter as compared to sun drying method. Texture of the persimmon decreased to the lowest strength within two days due to fruit softening, and then gradually increased due to water removal and skin formation of dehumidified persimmon. The dehumidified persimmon showed golden color appearance as that by sun drying. Glucose and fructose were the main sugars of persimmon, both of those sugars increased during the drying process. Sun drying persimmon showed a higher amounts of glucose and fructose than the dehumidified persimmon

Studies of Hsian-tsao (Mesona procumbens Hemsi.) Gelling Constituents Extraction and the Gel-forming Properties of Hsian-tsao Extracts

仙草(Mesona procumbens Hemsi.)是一種含有具凝膠性多糖類物質之草本植物，其經過適當鹼量添加與熬煮所得之萃取液，在添加2％澱粉時，會有韌性極強之凝膠特性。本研究比較仙草萃取時，添加0.05、0.1、0.3、0.5、0.7、l.0、1.2、1.4％碳酸鈉、碳酸氫鈉對仙草多糖類物質萃出之影響，結果顯示碳酸鈉處理之乾物抽出率與全可溶性固形物分別在19.32至44.85％與1.8至4.6ºBrix間，添加碳酸氫鈉萃取處理之乾物抽出率、全可溶性固形物則分別在13.90至38.95％與1.3至4.9ºBrix間，此顯示兩種鹼類皆有助於使仙草組織崩解並釋出其中之多糖類物質，而碳酸鈉處理較碳酸氫鈉處理對仙草植物中多糖類物質有更佳之抽出效果。又添加愈高量之碳酸鈉、碳酸氫鈉處理，會有愈多之仙草多糖類物質被抽出。綜合所製成仙草凍之凝膠品質、風味及口感，顯示以添加0.3至0.5％之碳酸鈉濃度進行萃取為最佳。 為比較碳酸鈉與碳酸氫鈉處理所得萃取液之凝膠性質，將此兩種鹼類處理所得之萃取液分別稀釋為含0.6、0.8、1.0、1.2、1.4％固形物之仙草溶液，再分別添加2.0、2.5、3-4.0％之小麥澱粉，各處理均顯示添加0.3％或0.5％碳酸鈉、碳酸氫鈉之萃取處理有最高之凝膠強度，其凝膠強度分別在42.0至130.0克／平方公分與36.3至110.6克／平方公分間，顯示以碳酸鈉處理所得之萃取液有較佳的凝膠品質；提高澱粉濃度有使仙草凝膠強度增加之趨勢，濃度以2.0-3.0％澱粉處理較宜，因添加4.0％小麥澱粉處理仙草凍之質感較差。 Hsian-tsao gel is a jello-type dessert popularly consumed in the Far East countries. The gel is prepared from the alkaline extract of Hsian-tsao (Mesona procumbensHemsl.) herb with the addition of approximately 2 % starch at boiling temperature. A dark-brownish gel will be formed after the solution is cooled. Extraction of Hsian-tsao gelling constituents using sodium carbonate and sodium bicarbonate at concentration ranged from 0.05 % to 1.4 % for 3 hours resulted in the total solids recoveris of 19.3 to 44.8 % and 13.9 to 39.0 %, respectively. These results are significantly higher than 12.2 % total solid srecovery of the herb extracted with distilled water. The higher concentration of sodium carbonate or sodium bicarbonate solution the more total solids is yielded. Hsian-tsao gels prepared from 1.0 Brix 0.3 % or 0.5 % sodium carbonate or sodium bicarbonate extracts with 2.0 % wheat starch added resulted in the most acceptable gel strength of 80 g/cm2. The higher the concentration of extract and the higher the starch added to the extract formed the greater gel strength of the gel

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

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