Browsing by Subject "Emulsion stability"
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    Formation and stability study of flavor oil emulsions stabilized by polyglycerol esters and by sucrose esters
    (Assumption University, 2016-05) Suwimon Ariyaprakai
    In this work, flavor oil emulsions contained 5 wt% oil and 0.75 wt% emulsifier were formulated by using different combinations between flavor oils and food emulsifiers. Orange oil (00), peppermint oil (PO), polyglycerol monostearate (PGE), and sucrose monostearate (SE) were employed to form emulsions by ultrasonic homogenization. Heat stability (storage at 100°C for 30 min) and freeze-thaw stability (storage at -20°C for 22 h. and at 30°C for 2 h.) of emulsions were investigated by observing droplets under a microscope, determining mean droplet sizes, and measuring amounts of destabilized oil. Ostwald ripening stability of emulsions was determined by measuring the droplet size distribution changes over 48 days of storage. The results showed that flavor oil emulsions stabilized by PGE and by SE were heat stable. Interestingly, flavo.r oil emulsions stabilized by PGE had better freeze- thaw stability compared to emulsions stabilized by SE. This property of PGE was suggested from polyglycerol interfacial layers reduced ice crystallization and reduced coalescence. The flavor oil emulsions stabilized by either PGE or SE underwent through Ostwald ripening destabilization and the ripening stability was improved by using mixed emulsifiers between PGE and SE. The information from this study could be useful for creating formulations of flavor oil emulsions that suitable for future applications in foods and beverages.
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    Freeze–thaw stability of edible oil-in-water emulsions stabilized by sucrose esters and Tweens
    ( 2015) Suwimon Ariyaprakai ; Kanitha Tananuwong
    This work aimed to investigate freeze thaw stability of 20 wt% coconut oil (CtO) and corn oil (CnO)- in-water emulsions stabilized by 1 wt% of various types of sucrose esters and Tweens. Sucrose esters composed mainly of sucrose monostearate (S1670), sucrose monopalmitate (P1670), sucrose monolaurate (L1695), Tween 20 (TW20), Tween 60 (TW60), and Tween 80 (TW80) were used. After all emulsions were frozen at 20 ± 2 C and thawed to room temperature, their stability was analyzed from visual appearance, optical micrographs, amounts of destabilized oil, and average particle sizes. The CtO emulsions stabilized by S1670 and P1670 were very stable, the CtO emulsions stabilized by L1695 partly destabilized, and the CtO emulsions stabilized by TW20, TW60, and TW80 mostly destabilized into oil layers separated on top. The excellent stability of CtO emulsions stabilized by S1670 and P1670 was also confirmed from similar thermograms obtained from differential scanning calorimeter after three cooling–heating cycles (40 C to 40 C to 40 C at 5 C/min). It was proposed here that S1670 and P1670 affected the interfacial fat crystallization and their interfacial layers protected CtO emulsions against partial coalescence. Differently for the case of CnO emulsions, the CnO droplets remained liquid during freezing. All CnO emulsions stabilized by any emulsifiers destabilized by coalescence since these small surfactants could not provide enough interfacial barriers.
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