The curd is affiliated with Rhodophyta, Polygalaceae, widely distributed in the tropical ocean. In China, it is mainly located in the coastal area of ​​Wenchang, Hainan, and it is one of the precious seaweed varieties for protection and reproduction. In addition, the Weizhou Island in Guangdong Province, the southern province of Taiwan, and the coastal areas of Lingao, Qionghai, and Zhangzhou in Hainan Province are also distributed, but the number is very small and there is no mining value.
The industrial production of the seaweed farm in Wenchang City proved that the curd is a high-quality raw material for the agar, washed with fresh water and sun-bleached with a gel yield of more than 38% and a gel strength of 600g/cm2. , powdered plastic 800g/cm2. In recent years, the quality of agar has been increasingly demanding in the market, especially in the export market, mainly due to the gel strength. The general requirement is not less than 1000g/cm2. We have studied the gel strength of the propolis and have achieved remarkable results. The report is as follows:
First, experimental materials and methods
1. Experimental materials (1) Flora, produced in the coastal area of ​​Guannan, Wenchang City, was repeatedly stored in fresh water and dried in the sun, bleached and stored in the warehouse.
(2) Sodium hydroxide, sodium hypochlorite, and oxalic acid are all commercially available.
(3) Gel Strength Tester AG1200 Agar Strength Tester, manufactured by Shenzhen Qiongjia Industrial Co., Ltd.
(4) Electric thermostatic water bath, C-86 type, produced by Guangzhou Yuexiu Medical Instrument Factory.
(5) Pressure cooker, working pressure 7010kpa, safety pressure 9010kpa, Guangdong Yangjiang Xiaodao General Factory production.
(6) Powder Press, Model XA-1, manufactured by Jiangsu Jiangyan Analytical Instrument Factory.
(7) Press dehydrator, self-made, with 5t jack press water.
(8) Constant temperature drying oven, GZX-OH-40X, produced by Shanghai Yuejin Medical Instrument Factory.
2. Experimental method (1) Alkaline treatment Weigh 25 g of the above mentioned broccoli in a 1000 ml beaker, add 500 ml of NaOH solution of different concentrations, heat to a certain temperature in a water bath, keep at a constant temperature for different periods of time, and wash and wash to neutrality. Soak 2 hours, add 500ml water, float with 10ml NaClO for 15 minutes, wash once, add 10ml of 10% H2C2O42H2O acidified for 15-25 minutes, wash to neutrality, and soak for 1 hour to extract the gum.
(2) Extracting the gum The acidified and bleached treated curd was added with 1000 ml of water in a pressure cooker to extract and exhaust it for 30 minutes, and then forcibly cooled. The industrial filter cloth with a surface with a torn filter press, coagulation, press dehydration, drying, smash. (Water about 11%).
(3) Determination of Gel Strength Weigh 1.5 g of powdered agar, add 98.5 g of water (1.5% of concentration), pressurize and dissolve in a pressure cooker for 30 minutes, replenish evaporation, then pour into 3 25 ml weighing bottles. It was cooled at 20°C for 10 hours and measured with a gel strength tester and expressed in g/cm2.
(4) Gel production rate = product weight 100% raw material weight
Second, the process of raw materials → alkaline treatment → cleaning → bleaching → cleaning → acidification → cleaning → gluing → filtration → cooling solidification → pressing dehydration → drying → smash.
Third, the results and discussion
1. The effect of alkali treatment on the gel strength It can be seen from the above test results that the alkali treatment can significantly increase the gel strength of propolis, from the original 800 g/cm2 to 1650 g/cm2, which is doubled. The curd was treated with different alkali concentrations. The alkali concentration was 2.5% and 5% best, and the intensity was 1650 g/cm2. The concentration continues to increase. After 15%, the strength gradually decreases, but at a concentration of 35%, the strength can still reach a high intensity of 1100 g/cm2. See Table 1.
Agar mainly consists of agar and agar esters. Agaroid is a long-chain structure consisting of agarose disaccharide as a basic repeating monomer, that is, 1,3-linked β-D-galactose and 1,4 linked α-3,6-lactone-L-half Lactose alternates long chain structures. Agar esters consist of derivatives of agarobiose. It is composed of various derivatives of agarobiose contained in red algae agar. The derivatives of agarobiose contained in various red algae agar are different, and thus the properties of various red algae are different. If the agar content is high in agar, the gel strength is high, whereas if the agar ester content is high, the strength is low. The presence of higher sulfate groups in agar esters is a major cause of low gel strength. Alkaline treatment can remove the sulfate groups attached to L-galactose or D-galactose C6 and C3 and convert them to 3,6-endoether-L-galactose or 6 endosteryl-D-galactose. In other words, the structure of the agar ester is converted into the agarine structure, so that the gel strength of the agar is increased after alkali treatment.
It can be seen from Table 2 that the alkali treatment time had little effect on the strength of the curd, and the strength reached 1350 g/cm2 for 1 hour, and the strength was 1450 g/cm2 for 10 hours, and the strength was 1450 g for 10 hours. /cm2; treatment 2-6 hours, the intensity is around 1600g/cm2.
Alkaline treatment temperature has little effect on the strength of curd, although the treatment temperature is 60-70 °C, the intensity is lower, but there are still 1200-1350g/cm2. While the treatment temperature continued to rise to 100°C, the gel strength remained between 1500-1650 g/cm2 with little change. See Table 3.
2. The effect of alkali treatment on the gum yield of curd rubber can be seen from the test results. After the alkali treatment of the curd, the rubber production rate is lower than 41.2% without the alkali treatment. This is due to the fact that the curd is treated with hot alkali. The reason that some of the colloids are dissolved in the lye can be proved by thickening the lye after multiple treatments.
From Table 1, it can be seen that when the alkali concentration is 2.5% and 5%, the highest gel yield is about 38.5%; the alkali concentration is between 10% and 25%, and there is no major change in the rate of gum production, only alkaline After the concentration rose to 30%, the rubber production rate decreased greatly. At a concentration of 35%, the rubber production rate dropped to 33.6%.
The alkali treatment time was within 3 hours and the gel yield was high, reaching 38.6. Later, with the extension of time, the rate of rubber production also gradually decreased. After 10 hours of treatment, the rate of rubber production dropped to 29.6%, and the drop rate was relatively large, as shown in Table 2.
From the alkali treatment temperature point of view, the temperature between 70-80 °C can get 38.7% -38.6% of the high rate of production of plastic, the temperature continues to rise above 85 °C, a considerable benefit.
Fourth, summary
1. After the hot-alkali modification treatment, the gel strength of the curd was greatly improved from the original 800 g/cm2 to 1650 g/cm2, which was doubled.
2. After hot-alkali modification treatment, the rate of gum production decreased.
3. The optimum conditions for the modification of high-strength gellanine were: alkali concentration 2.5%, time 3 hours, and temperature 75-80°C.
The industrial production of the seaweed farm in Wenchang City proved that the curd is a high-quality raw material for the agar, washed with fresh water and sun-bleached with a gel yield of more than 38% and a gel strength of 600g/cm2. , powdered plastic 800g/cm2. In recent years, the quality of agar has been increasingly demanding in the market, especially in the export market, mainly due to the gel strength. The general requirement is not less than 1000g/cm2. We have studied the gel strength of the propolis and have achieved remarkable results. The report is as follows:
First, experimental materials and methods
1. Experimental materials (1) Flora, produced in the coastal area of ​​Guannan, Wenchang City, was repeatedly stored in fresh water and dried in the sun, bleached and stored in the warehouse.
(2) Sodium hydroxide, sodium hypochlorite, and oxalic acid are all commercially available.
(3) Gel Strength Tester AG1200 Agar Strength Tester, manufactured by Shenzhen Qiongjia Industrial Co., Ltd.
(4) Electric thermostatic water bath, C-86 type, produced by Guangzhou Yuexiu Medical Instrument Factory.
(5) Pressure cooker, working pressure 7010kpa, safety pressure 9010kpa, Guangdong Yangjiang Xiaodao General Factory production.
(6) Powder Press, Model XA-1, manufactured by Jiangsu Jiangyan Analytical Instrument Factory.
(7) Press dehydrator, self-made, with 5t jack press water.
(8) Constant temperature drying oven, GZX-OH-40X, produced by Shanghai Yuejin Medical Instrument Factory.
2. Experimental method (1) Alkaline treatment Weigh 25 g of the above mentioned broccoli in a 1000 ml beaker, add 500 ml of NaOH solution of different concentrations, heat to a certain temperature in a water bath, keep at a constant temperature for different periods of time, and wash and wash to neutrality. Soak 2 hours, add 500ml water, float with 10ml NaClO for 15 minutes, wash once, add 10ml of 10% H2C2O42H2O acidified for 15-25 minutes, wash to neutrality, and soak for 1 hour to extract the gum.
(2) Extracting the gum The acidified and bleached treated curd was added with 1000 ml of water in a pressure cooker to extract and exhaust it for 30 minutes, and then forcibly cooled. The industrial filter cloth with a surface with a torn filter press, coagulation, press dehydration, drying, smash. (Water about 11%).
(3) Determination of Gel Strength Weigh 1.5 g of powdered agar, add 98.5 g of water (1.5% of concentration), pressurize and dissolve in a pressure cooker for 30 minutes, replenish evaporation, then pour into 3 25 ml weighing bottles. It was cooled at 20°C for 10 hours and measured with a gel strength tester and expressed in g/cm2.
(4) Gel production rate = product weight 100% raw material weight
Second, the process of raw materials → alkaline treatment → cleaning → bleaching → cleaning → acidification → cleaning → gluing → filtration → cooling solidification → pressing dehydration → drying → smash.
Third, the results and discussion
1. The effect of alkali treatment on the gel strength It can be seen from the above test results that the alkali treatment can significantly increase the gel strength of propolis, from the original 800 g/cm2 to 1650 g/cm2, which is doubled. The curd was treated with different alkali concentrations. The alkali concentration was 2.5% and 5% best, and the intensity was 1650 g/cm2. The concentration continues to increase. After 15%, the strength gradually decreases, but at a concentration of 35%, the strength can still reach a high intensity of 1100 g/cm2. See Table 1.
Agar mainly consists of agar and agar esters. Agaroid is a long-chain structure consisting of agarose disaccharide as a basic repeating monomer, that is, 1,3-linked β-D-galactose and 1,4 linked α-3,6-lactone-L-half Lactose alternates long chain structures. Agar esters consist of derivatives of agarobiose. It is composed of various derivatives of agarobiose contained in red algae agar. The derivatives of agarobiose contained in various red algae agar are different, and thus the properties of various red algae are different. If the agar content is high in agar, the gel strength is high, whereas if the agar ester content is high, the strength is low. The presence of higher sulfate groups in agar esters is a major cause of low gel strength. Alkaline treatment can remove the sulfate groups attached to L-galactose or D-galactose C6 and C3 and convert them to 3,6-endoether-L-galactose or 6 endosteryl-D-galactose. In other words, the structure of the agar ester is converted into the agarine structure, so that the gel strength of the agar is increased after alkali treatment.
It can be seen from Table 2 that the alkali treatment time had little effect on the strength of the curd, and the strength reached 1350 g/cm2 for 1 hour, and the strength was 1450 g/cm2 for 10 hours, and the strength was 1450 g for 10 hours. /cm2; treatment 2-6 hours, the intensity is around 1600g/cm2.
Alkaline treatment temperature has little effect on the strength of curd, although the treatment temperature is 60-70 °C, the intensity is lower, but there are still 1200-1350g/cm2. While the treatment temperature continued to rise to 100°C, the gel strength remained between 1500-1650 g/cm2 with little change. See Table 3.
2. The effect of alkali treatment on the gum yield of curd rubber can be seen from the test results. After the alkali treatment of the curd, the rubber production rate is lower than 41.2% without the alkali treatment. This is due to the fact that the curd is treated with hot alkali. The reason that some of the colloids are dissolved in the lye can be proved by thickening the lye after multiple treatments.
From Table 1, it can be seen that when the alkali concentration is 2.5% and 5%, the highest gel yield is about 38.5%; the alkali concentration is between 10% and 25%, and there is no major change in the rate of gum production, only alkaline After the concentration rose to 30%, the rubber production rate decreased greatly. At a concentration of 35%, the rubber production rate dropped to 33.6%.
The alkali treatment time was within 3 hours and the gel yield was high, reaching 38.6. Later, with the extension of time, the rate of rubber production also gradually decreased. After 10 hours of treatment, the rate of rubber production dropped to 29.6%, and the drop rate was relatively large, as shown in Table 2.
From the alkali treatment temperature point of view, the temperature between 70-80 °C can get 38.7% -38.6% of the high rate of production of plastic, the temperature continues to rise above 85 °C, a considerable benefit.
Fourth, summary
1. After the hot-alkali modification treatment, the gel strength of the curd was greatly improved from the original 800 g/cm2 to 1650 g/cm2, which was doubled.
2. After hot-alkali modification treatment, the rate of gum production decreased.
3. The optimum conditions for the modification of high-strength gellanine were: alkali concentration 2.5%, time 3 hours, and temperature 75-80°C.