(492i) Effects of Spray Drying Temperature On Release Characteristics of Nisin From Biopolymer Microcapsules

In this work, spray drying was used to microencapsulate nisin in food biopolymer corn zein, and release properties of nisin were studied for capsules produced at different spray drying temperatures. Nisin was extracted with 50% (v/v) aqueous ethanol for 6 hours from a 2.5% commercial preparation at a solids concentration of 6 mg/mL. After centrifugation, the supernatant was transferred and adjusted to 70% ethanol (v/v). Zein (2%, w/v) was then dissolved in the extract, and the solution was spray-dried at four inlet temperatures from 75 to 120 ºC. In vitro release studies were performed in aqueous buffers at pH 2, 6, and 8. At pH 2, all samples showed 100% release at the first time point of 30 min. At pH 6, the sample prepared at a lower temperature showed a higher extent of nisin release at the same time point and a longer time to reach release equilibrium. Similar trends were observed at pH 8 but the amount of released nisin was much lower (< 20% for all samples after 200 hours). Additionally, sustained and more complete release was achieved at pH 8 after adding 0.5 M NaCl in release buffers, possibly due to reduced electrostatic attraction between nisin and zein. Findings from this work showed that release properties of nisin can be manipulated by spray drying temperature alone.