利用多層包埋技術維持植酸酶於受熱時之活性

Multilayer encapsulation maintaining enzyme activity of phytase during thermal treatment

陳冠融(Kuan-Jung Chen)

指導教授 ： 蔣丙煌

國立臺灣大學/生物資源暨農學院/食品科技研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01240

摘要

植酸酶是常見的飼料添加物，隨著環保意識抬頭，在2000年以後應用越來越廣泛，其主要功用是分解植物中所含有的植酸，以增加無機磷的生物利用率，而植酸酶屬於熱敏感型酵素，外界溫度高於80℃會有劇烈失活的現象。由於飼料打粒(pelleting)的過程需使用高溫蒸氣，會使植酸酶失活，因此目前大部分都是於飼料打粒後，以外噴的方式塗佈液態之植酸酶於飼料顆粒上，唯外噴存在塗佈不均勻及操作之不便等問題，造成飼料加工上之困擾。因此，本研究旨在藉由多層包埋的方式來製作植酸酶乾燥粉粒，增加植酸酶之熱穩定性，所生產之植酸酶乾燥粉粒可以直接與飼料混合，使飼料之加工流程更簡單便利。本研究之最大的課題為選擇適當的包材與搭配適當的包埋技術。
由先前的研究發現甘露醇具有當作噴霧乾燥過程中載體的能力且具備比熱隨溫度上升而上升的性質。流動床包覆是在製藥工業上常見的包覆方式，壁材的選擇上須具有黏著性，以利在乾燥的過程中包裹於粉體外。本研究係利用甘露醇當作植酸酶在噴霧乾燥時之載體，使植酸酶與甘露醇形成Matrix的構造，再以阿拉伯膠與海藻糖在噴霧乾燥的粉體外進行包衣。目前實驗結果顯示，以此包覆方式能夠有效提高植酸酶在高溫下的耐受性，在115℃的環境下乾熱處理10分鐘後，利用甘露醇噴霧乾燥法包埋之植酸酶可維持82%的活性，而再以阿拉伯膠進行流動床包埋則可維持90%以上的活性。而在100℃溼熱處理5分鐘僅有有經過流動床進行二層包埋的植酸酶粉體具有部分活性。本研究結果除了驗證甘露醇與變性大豆分離蛋白具有做為噴霧乾燥時包埋生物活性物質之載體外亦可推斷藉由噴霧乾燥與流動床包埋之植酸酶粉體是能夠提升植酸酶之熱穩定性。

關鍵字

植酸酶 ； 打粒 ； 噴霧乾燥 ； 流動床

並列摘要

Phytases have gathered considerable attention in recent years due to their applications in human and animal nutrition, environmental protection and biotechnology. Phytase is incorporated into commercial poultry, swine, and fish diets to improve the availability of phosphorus, minerals, amino acids, and energy. However, phytase is thermally unstable, loss of activity often occure at processing temperature higher than 80C. As the temperature goes over 87C during steam pelleting of feed, the phytase activity would decrease drastically 66%.
Previous studies have shown that the encapsulation is a good method to increase the enzyme thermal stability. Therefore, the development of a suitable method to protect phytase with high thermal tolerance is a big challenge for feed industry. The encapsulation technology has been widely used by the food industry for more than 60 years. Encapsulation involves entrapping active compounds/ enzyme(s) within a semipermeable membrane. There are lots of encapsulation techniques such as emulsification, solvent evaporation, phase separation, co-crystallization, etc., but spray-drying is the most commonly used technology due to its continuous production and easiness of industrialization. But, how to choose the suitable wall material is still a big challenge.
The objective of this study is to investigate suitable enzyme encapsulation methodology to improve thermal stability. For this purpose, we have developed two different encapsulation systems: System A, spray dry powder with D-mannitol and soy protein isolate; and System B, fluid bed powder with gum arabic and trehalose. System A composed of D-mannitol(15%), soy protein isolated(5%), while System B composed of gum Arabic(20%), trehalose(5%)
Phytase on exposure to 115C, dry heat treatment for 10 minutes shows 82% activity retention when encapsulated with D-mannitol and soy protein isolate spray drying, while gum arabic and trehalose encapsulation by fluid bed showed 90% activity retention. During wet heat treatment for 5 minutes only the phytase encapsulated by fluid bed could keep partial activity. The research have demonstrated that encapsulation with suitable bio-polymers using spray drying and fluid bed technology could indeed protect phytase from losing enzyme activity.

並列關鍵字

phytase ； pelleting ； spray dry ； fluid bed

參考文獻

Richard T. Lovell, e. a., Nutrient Requirements of Fish. National Academy Press Washington, D.C. 1993.

Augustin, M. A.; Hemar, Y., Nano- and micro-structured assemblies for encapsulation of food ingredients. Chemical Society reviews 2009, 38, 902-12.

Barreca, D.; Lagana, G.; Magazu, S.; Migliardo, F.; Gattuso, G.; Bellocco, E., FTIR, ESI-MS, VT-NMR and SANS study of trehalose thermal stabilization of lysozyme. International journal of biological macromolecules 2014, 63, 225-32.

Barrow, C. J.; Nolan, C.; Holub, B. J., Bioequivalence of encapsulated and microencapsulated fish-oil supplementation. Journal of Functional Foods 2009, 1, 38-43.

Bernard F. Gibbs, S. K., Inteaz Alli and Catherine N. Mulligan, Encapsulation in the food industry : a review. International Journal of Food Sciences and Nutrition 1999.