Determination of critical storage conditions of coffee oil microcapsules by coupling water sorption isotherms and glass transition temperature

Author(s)

Frascareli, Elen Cristina ^[1] ; Silva, Vanessa Martins ^[1] ; Tonon, Renata Valeriano ^{[2, 1]} ; Hubinger, Mriam Dupas ^[1]

Affiliation

^[1] Univ Campinas UNICAMP, Sch Food Engn, Dept Food Engn, BR-13083862 Campinas, SP - Brazil

^[2] Embrapa Food Technol, BR-23020470 Rio De Janeiro, RJ - Brazil

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY; v. 47, n. 5, p. 1044-1054, MAY 2012.
• Web of Science Citations: 17

Abstract

Coffee oil microcapsules were produced by spray-drying using as encapsulating agents gum Arabic, whey protein isolate (WPI) and mixtures of maltodextrin (MD) and WPI, at three different proportions (3:1, 1:1 and 1:3). Sorption isotherms were determined by the gravimetric method, and the glass transition temperature (Tg) was measured by differential scanning calorimetry. Microcapsules produced with gum Arabic showed the highest water adsorption and underwent a stronger water plasticising effect. At the highest water activity (0.843), this sample had a Tg value of -18.3 degrees C, while those produced with WPI at higher proportions showed values around 25 and 30 degrees C. The good fit of experimental data by Guggenheim-Anderson-de Boer and GordonTaylor models allowed the determination of the critical storage conditions, at which powders are not susceptible to deteriorative physical changes. The samples produced with 1:1 and 1:3 of MD/WPI were the most stable ones, showing critical water activity values of 0.890 and 0.938, respectively. (AU)

• FAPESP's process: 09/54137-1 - Acquisition of a particle size/distribution analyzer, a zeta potential measurement system, a spray dryer, and an ultra-high-pressure liquid chromatograph/mass spectrometer
• Grantee: Miriam Dupas Hubinger
• Support Opportunities: Multi-user Equipment Program