Ultrafiltration of coconut milk emulsion "gata" using cellulose acetate and polyamide membranes

Issue Date

9-2006

Abstract

Cellulose acetate (CA) membranes were prepared from 25% CA in N,N-dimethylformamide (DMF) and were used in the ultrafiltration (UF) of coconut milk emulsion (CME) with and without emulsifier, namely sodium caseinate or carrageenan. All UF fractions were analyzed for protein, carbohydrate, oil and phosphate. High values of the membrane rejection coefficient (σr) for protein and carbohydrate were obtained, especially with added emulsifier; the σr, values for phosphate and oil decreased in the presence of emulsifier. The retentates after ultrafiltration of CME, with and without added sodium caseinate or carrageenan, were tested for stability. After 3 min of immersing the samples in a hot water bath (80 °C), the retentate without added emulsifier separated into two distinct liquid layers. No change was observed in the retentate with added emulsifier, which shows that ultrafiltration of CME in the presence of added emulsifier, either sodium caseinate or carrageenan, enhanced the stability of CME. Two sets of polyamide membranes were also prepared from 30% polyamide (nylon-6) and were used in the ultrafiltration of CME. Membrane rejection of coconut oil was 100% while σ, values were 94.7% and 88.4% for membranes prepared from dope mixtures containing H2SO4 and HCI, respectively. The results were interpreted in terms of the effectiveness of UF in facilitating the separation of the oil-rich and aqueous phases, i.e. creaming, of CME. Addition of either sodium caseinate or carrageenan to CME during ultrafiltration resulted in dehydration and concentration of the oil and most soluble components of CME in the retentate without significant creaming.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

89

Issue

3

Page

268-279

Document Type

Article

Language

English

Subject

Cellulosic membranes, Coconut milk, Oil-in-water emulsion, Polyamide membranes, Ultrafiltration

Digital Copy

none

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