Studies on physical, mechanical, and industrially relevant properties of spray-dried dairy systems

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dc.contributor.advisor Roos, Yrjö H. en
dc.contributor.advisor Miao, Song en Li, Runjing 2017-05-03T12:16:39Z 2017 2017
dc.identifier.citation Li, R. 2017. Studies on physical, mechanical, and industrially relevant properties of spray-dried dairy systems. PhD Thesis, University College Cork. en
dc.identifier.endpage 207 en
dc.description.abstract Engineering properties of food solids are highly dependent on their physical state, i.e. amorphous, crystalline, or liquid. Understanding glass transition-related relaxations and their coupling with engineering properties of food materials is highly essential. The present study investigated the physical and mechanical properties of two model dairy solids systems: (i) lactose/milk protein isolate (MPI) solids systems produced by a laboratory scale spray dryer and a pilot scale spray dryer, respectively; (ii) lactose/whey protein isolate (WPI) (4:1) mixtures pre-crystallised before spray drying. Dairy solids with smaller size particles showed lower glass transition temperatures (Tg) after equilibration at 0.11-0.33 aw. For lactose/WPI (4:1) mixtures with different crystallinity, increasing the amount of crystalline lactose had no significant influence on the glass transition temperatures and the initial crystallization temperatures at 0.11-0.44 aw. The present study also investigated the flow properties of two dairy-based solids systems: (i) lactose/MPI solids systems; (ii) lactose/WPI solids systems pre-crystallized before spray drying. Lactose/MPI mixtures with higher lactose contents showed better flowability at 0 and 44% relative humidity (RH). For pre-crystallization systems, flow function tests indicated that dairy solid with 11.2% crystallinity was more easy-flowing than lactose/WPI mixtures with 1.0, 29.2 and 46.8% crystallintiy. At last, the effect of formulation on encapsulation properties and flavor release of amorphous matrix was studied. Firstly, lactose/WPI (4:1, 1:1, and 1:4) mixtures, or WPI were used as wall systems. Wall material consisting of lactose/WPI (4:1) mixture had significantly (P < 0.05) higher encapsulation efficiency. Then, the encapsulation properties of dairy solids using lactose/WPI (4:1) or lactose/maltodextrin (MD)/WPI (3:1:1 or 1:3:1) mixtures as wall systems were determined. Wall systems consisting with lactose/MD (13-17)/WPI (1:3:1) mixtures and lactose/MD (23-27)/WPI mixtures had higher flavor retention than other wall systems after equilibration at high water activity (≥ 0.54 aw). en
dc.description.sponsorship Department of Agriculture, Food and the Marine (FIRM Grant 11-F-001) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2017, Runjing Li. en
dc.rights.uri en
dc.subject Dairy powders en
dc.subject Glass transition en
dc.subject Mechanical properties en
dc.subject Flow properties en
dc.subject Encapsulation properties en
dc.title Studies on physical, mechanical, and industrially relevant properties of spray-dried dairy systems en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Food Science and Technology) en
dc.internal.availability Full text available en
dc.description.version Accepted Version
dc.contributor.funder Department of Agriculture, Food and the Marine en
dc.description.status Not peer reviewed en Food and Nutritional Sciences en Teagasc en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.internal.conferring Summer 2017 en

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