การเพิ่มอายุการเก็บรักษายีสต์ขนมปังแห้งด้วยสารกันหืน

Increase Shelf Life of Dry Baker's Yeast with Antioxidant

Name: วนัสยา สุอังคะวาทิน

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Active dried yeast

; Antioxidant

; Additives

; Formulation

; Shelf life

Abstract: For increasing yeast viability after drying process and its shelf life storage, the production of activedried yeast (ADY) is normally supplemented with suitable additives. In this research, types andconcentrations of antioxidants at range between 0.025-0.5%(w/w) are investigated, concomitantwith basic additives such as 1.15%(w/w) guar gum, 7.5%(w/w) sorbitan monosterate and 1 %(w/w)calcium monohydrogen phosphate. The synthetic antioxidants such as 0.15%(w/w) propyl gallate,0.05%(w/w) butylated hydroxyanisole and 0.05%(w/w) butylated hydroxytoluene gave 34.17%,42.46% and 42.36% of viability respectively. The natural antioxidants such as 0.03%(w/w) ascorbicacid gave 39.34% of viability and 0.05%(w/w) citric acid gave the highest viability of 69.29%comparison with non-supplementation of antioxidant (42.25% of viability). When compared thestorage shelf life at 4-8OC, it was found that after 20 weeks all non-supplemented dried yeast died,while those supplemented with antioxidant could decrease viability about 1.5-14 fold, especiallywith 0.3%(w/w) butylated hydroxytoluene decreased a little of viability about 1.5 fold. Thecombination of 0.05%(w/w) citric acid and 0.3%(w/w) butylated hydroxytoluene and basicadditives gave 60.03% of viability and only 1.3 fold of viability decreased at 40 weeks of shelflife. It can be concluded that this formulation is interesting to be used for applying in dry yeastproduction in the future.The study on CO, production by Sponge test at 22 ml of initial volume using 4.0 X 10กำลัง8 CFUIml ofviable cells was carried out. It was found that Fermipan was effective on CO, production (40 ml) at75 minutes. In case of cream yeast and dried yeast supplementation with combination of 0.05%(w/w) citric acid and 0.3%(w/w) butylated hydroxytoluene, the Sponge tests at 31 ml and 27 ml ofvolume respectively, were obtained at the same time.Moreover, the quantity of trehalose in yeast cells influences on yeast viability after drying process.The formulation of high trehalose containing yeast cell (22.29%, w/w) with combination ofsupplemented 0.05%(w/w) citric acid and 0.3%(w/w) butylated hydroxytoluene gave an increase in66.74% viability after drying process, while low trehalose containing yeast cell (1.91%, w/w) couldsustained 60.1% of viability. It was shown that trehalose in yeast cell could increase viability ofyeast during drying process.Mathematic model C = (1-K)CoEXP (-Kdexpt)+ (KCo - Kd,t) was applied for studying death raceof dried yeast. It was found that yeast viability from experiment was comparable with that frommodel. This can be concluded that (1) the concentration of antioxidant at range between 0.01-0.3%(w/w) influences on shelf life, high concentration of antioxidant have more efficiency to increaseshelf life, (2) a mixed well formulated cell decrease a little in death rate, while non-mixed wellformulated cell decreased rapidly in that value as exponential rate.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: รศ.ดร. ยุวพิน ด่านดุสิตาพันธ์

Role: อาจารย์ที่ปรึกษา

Created: 2545

Issued: 2005-09-20

Modified: 2006-05-10

วิทยานิพนธ์/Thesis

ISBN: 9749551559

CallNumber: BIT384

tha

DegreeName: วิทยาศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีชีวภาพ

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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