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    生物降解澱粉顆粒的酶改性方法

    生物降解澱粉顆粒的酶改性方法

    網址:http://www.chuntianwenshi.com 手機頁麵二維碼 2022-06-16 18:31:51    

    為了提高澱粉顆粒對酶的敏感性,可以對顆粒進行適當的預處理以提高反應效率。目前常用的預處理方法有水熱處理、超聲波處理、凍融循環處理和機械處理等。水熱處理作為一種物理預處理方式,包括濕熱處理和退火處理,且這兩種方式都會保留澱粉的顆粒形態。這兩種方式都需要控製處理過程中澱粉的含水量、溫度以及加熱時間。
    In order to improve the sensitivity of starch granules to enzymes, the granules can be pretreated appropriately to improve the reaction efficiency. At present, the commonly used pretreatment methods include hydrothermal treatment, ultrasonic treatment, freeze-thaw cycle treatment and mechanical treatment. As a kind of physical pretreatment, hydrothermal treatment includes moist heat treatment and annealing treatment, and both of them will retain the granular morphology of starch. Both methods need to control the water content, temperature and heating time of starch during the treatment.
    酶法改性澱粉顆粒要保證在酶改性的過程中和改性後澱粉的顆粒形態始終得以保留。澱粉的糊化起始溫度多在60 ℃左右,所以酶改性的溫度一般不超過60 ℃。
    The granule morphology of starch modified by enzyme should be kept during the process of enzyme modification and after modification. The initial gelatinization temperature of starch is usually about 60 ℃, so the temperature of enzymatic modification is generally not more than 60 ℃.
    達到佳的改性時間後,添加酸或堿滅酶,在適當條件下離心後收集的澱粉經過蒸餾水或乙醇溶液洗滌、幹燥,後研磨過篩製得酶法改性的澱粉顆粒。實驗室研究酶法改性澱粉顆粒常用的幹燥方法有真空幹燥、冷凍幹燥和烘箱幹燥等。
    After the optimal modification time is reached, acid or alkali is added to kill the enzyme, the starch collected after centrifugation under appropriate conditions is washed and dried with distilled water or ethanol solution, and then ground and sieved to obtain enzyme modified starch particles. Vacuum drying, freeze drying and oven drying are the common drying methods for enzymatic modified starch granules.
    改性生物降解顆粒的形態結構通常采用掃描電子顯微鏡進行分析。掃描電子顯微鏡圖中可以清晰地觀察到顆粒表麵的凹痕和孔洞,還可以根據不同酶解時間澱粉顆粒的電子顯微鏡圖推測出酶對澱粉顆粒的作用方式和特點。
    The morphology of modified biodegradable particles is usually analyzed by scanning electron microscope. The dents and holes on the surface of starch granules can be clearly observed in the scanning electron microscope. The action mode and characteristics of enzymes on starch granules can also be inferred from the electron microscope images of starch granules with different enzymatic hydrolysis time.
    生物降解顆粒
    酶改性對澱粉顆粒的晶型和結晶度有不同程度的影響,這取決於酶和澱粉的種類以及改性時間。經過分支酶和轉葡糖苷酶的組合修飾後,馬鈴薯澱粉的晶型由B型結晶轉變為C型結晶。馬鈴薯澱粉顆粒晶型的轉變可能是經酶修飾後,支鏈澱粉的B1鏈含量增加,顆粒非結晶區的分支密度增加,使分支點間距離的縮短,從而導致澱粉的自發重結晶。
    Enzyme modification has different effects on the crystal form and crystallinity of starch granules, which depends on the type of enzyme and starch and the modification time. After modification with branching enzyme and transglucosidase, the crystalline form of potato starch changed from B-type to C-type. The transformation of potato starch granule crystal form may be that after enzyme modification, the B1 chain content of amylopectin increases, the branching density of the non crystalline region of the granule increases, and the distance between branching points shortens, resulting in the spontaneous recrystallization of starch.
    由於對澱粉顆粒的改性在非糊化條件下進行,所以改性澱粉仍然保留了糊化特性,並且酶對澱粉顆粒的修飾會改變其糊化溫度和糊化焓。分支酶修飾木薯澱粉顆粒引起改性澱粉糊化起始溫度、糊化峰值溫度和糊化焓升高。糊化起始溫度的升高是由於澱粉顆粒的形態發生了變化,以及直鏈澱粉發生重結晶。糊化焓的提高表明改性使澱粉顆粒結構的穩定性提高。
    Because the modification of starch granules was carried out under non gelatinization conditions, the gelatinization properties of modified starch were still retained, and the gelatinization temperature and enthalpy of starch granules were changed by enzyme modification. Modification of cassava starch granules by branching enzymes resulted in the increase of gelatinization initial temperature, gelatinization peak temperature and gelatinization enthalpy of modified starch. The increase of gelatinization initial temperature was due to the change of starch granule morphology and the recrystallization of amylose. The increase of gelatinization enthalpy showed that the stability of starch granule structure was improved by modification.
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