Mr. Ekasit Onsaard 4483011

Thesis Proposal Functional Properties of Coconut Protein and Its Role on Emulsion Stability of Coconut Milk Products Advisory Committee: Dr. Manee Vittavanont Assoc.Prof.Dr. Sukoncheun Srigam Assoc.Prof.Dr. David Julian McClements Prof.Dr. Eric A. Decker Mr. Ekasit Onsaard 4483011 Department of Food Technology, Graduate School, Prince of Songkla University

Scope • Introduction • Objective • Scope of the research • Materials and methods • Expected outcome • Research plan

Introduction

Figure 1 Cross section of a coconut Source: Canapi, et al. (1996) Coconut

Coconut Meat Table 1 Proximate composition of mature coconut kernel meat Source: Modified from Dendy and Timmins (1973); Grimwood (1975); Balachandran, et. al. (1985); Chakraborty (1985); Kwon et al. (1996)

Utilization of coconut meat • Coconut milk • Coconut oil

(1) Dried coconut meat (copra) • mechanical press • Oil Coconut meal • Protein isolate • Fresh coconut meat • (2)hydraulic press • Coconut milk • centrifuge • Cream Skim milk • Protein isolate • Water Oil Protein Protein concentration Oil extraction

Coconut milk The term “Coconut milk” is referred to a white, opaque protein-oil-water emulsion obtained by pressing grated solid coconut endosperm with or without addition of potable water or liquid endosperm (Seow and Gwee, 1997). Weak Point - Short-term physical and microbial stability

Problems • Emulsion instability Thermal processing of coconut milk products • Pasteurization • Sterilization • UHT

Objectives 1. To investigate type, characteristics and proportion of coconut proteins in coconut meat and coconut milk 2. To evaluate functional properties of major protein fractions in coconut milk 3. To study role of main coconut proteins on emulsion stability of thermally processed coconut milk products

Scope of the Research In this research project, coconut proteins will be extracted and fractionated from coconut meat and coconut milk. Then their type, proportion, physicochemical characteristics, and functional properties will be investigated. The roles of main protein fractions and some factors affecting on emulsion stability of thermally processed coconut milk will be examined in a model system.

Coconut samples Materials The mature coconut (11-13 month) used as a source of coconut meat throughout this research is a native coconut palm variety, which is grown in Thanam district, Pattani province. Chemicals (1) All chemicals used in analytical method are analytical grade. (2) Chemicals used as solvent for oil extraction from coconut meat are commercial grade.

Methods Part I 1. Study on characteristic and chemical compositions of coconut meat and coconut milk 1.1 Preparation of coconut meat, coconut milk, coconut cream, and coconut skim milk 1.2 Physical properties and chemical composition of coconut meat and coconut milk. 2. Study on types and proportion of coconut protein in coconut meat, coconut cream and coconut skim milk 2.1 Preparation of coconut cream protein; CCP 2.2 Preparation of coconut skim milk protein; CSP 2.3 Types, concentration and proportion of each protein fractions in coconut meat, coconut cream and coconut skim milk

Study on characteristic and chemical compositions of coconut meat and coconut milk 1.1 Preparation of coconut meat, coconut milk, coconut cream, and coconut skim milk (1)

(2) (3)

1.2 Physical properties and chemical composition of coconut meat and coconut milk (1) Coconut meat (section 1.1(1)) - protein, fat, moisture and ash (AOAC,1999) (2) Coconut milk, coconut cream and coconut skim milk (section 1.1(2) and 1.1(3)) - pH (pH meter) - Viscosity (Brookfield viscometer) - Fat (Mojonnior Ether Extraction; AOAC,1999)), protein, moisture and ash (same method in 1.2(1))

2. Study on types and proportion of coconut protein in coconut meat, coconut cream and coconut skim milk 2.1 Preparation of coconut cream protein; CCP Coconut milk and coconut cream will be used to prepare CCP by two methods as follows: (1)

(2) CCP will be freeze-dried and analyzed for content of protein, fat, moisture, and ash. CCP will be kept at -200C until further used for protein fractionation.

2.2 Preparation of coconut skim milk protein; CSP (1) Coconut skim milk will be filtered through 0.45 m by microfiltration. The CSP will be concentrated and isolated as follows: (2) The CPC and isolate will be freeze-dried and analyzed for the content of protein, fat, moisture and ash.

2.3 Types, concentration and proportion of each protein fractions in coconut meat, coconut cream and coconut skim milk Defatted coconut meat (1.1(1)), CCP (2.1) and CSP (2.2) will be extracted and fractionated using method used by Kwon et al., (1996).

Part II 3. Study on characteristics and functional properties of coconut proteins 3.1 Characterization of coconut proteins 3.2 Determination of functional properties of coconut proteins

3. Study on characteristics and functional properties of coconut proteins 3.1 Characterization of coconut proteins Some important physico-chemical characteristics of the CCP (2.1), CSP(2.2) and each protein fraction of coconut meat, CCP and CSP from section 2.3 will be determined as follows: 3.1.1 Molecular weight of coconut proteins - Size exclusion chromatography (Hagenmaier et al., 1972a) - Sodium dodecyl sulfate polycrylamide gel electrophoresis (SDS-PAGE) (Laemmli, 1970) 3.1.2 Isoelectric point; pI (Isoelectric Fousing Electrophoresis; IEF) 3.1.3 Thermal denaturation behavior (Differential scanning calorimetric; DSC) 3.1.4 Amino acid profile (Kwon et al., 1996)

3.2 Determination of functional properties of coconut proteins Some functional properties of CCP, CSP and their main protein fractions will be determined within pH condition range from 4-7 and NaCl concentration of 0-2.5 M. 3.2.1 Solubility (Chobert et al., 1988) 3.2.2 Emulsifying properties - Emulsion capacity (Wang and Kinsella, 1976) - Emulsion activity (Pearce and Kinsella, 1978) - Emulsion stability (Chobert et al., 1988)

3.2.3 Gelling properties - Least gelling concentration - Gelling temperature (gelling point) (Rheometer) 3.2.4 Water holding capacity;WHC (Tomotake et al.,2002) 3.2.5 Fat absorption capacity; FAC (Tomotake et al.,2002)

Part III 4. Study on the role of main protein fractions of coconut milk and the effect of heat treatment on emulsion stability of coconut milk model system 4.1 Preparation of a model system of coconut milk emulsion 4.2 Effects of type, proportion and concentration of main protein fractions of coconut milk on emulsion stability of coconut milk in model system 4.3 Effects of heat treatment at various levels on emulsion stability of coconut milk in model system

4. Study on the role of main protein fractions of coconut milk and the effect of heat treatment on emulsion stability of coconut milk model system 4.1 Preparation of a model system of coconut milk emulsion Physical properties of coconut milk model system and coconut milk containing the same protein and fat content, and pH value will then be determined as follows: - Emulsion stability;ES (Dagorn-Scaviner et al., 1987) - Droplet size and distribution (laser light scattering) - Viscosity (Brookfield viscometer)

4.2 Effects of type, proportion and concentration of main protein fractions of coconut milk on emulsion stability of coconut milk in model system Main protein fractions of CCP and CSP from section 2.3 will be used throughout this study as follows: (1) Coconut milk containing various type of predominant fractions of CCP and CSP will be prepared with the same procedure as 4.1. Physical properties of the obtained coconut milk will be determined by the same method used in 4.1 in comparison with the standard coconut milk model system.

(2)Coconut milk containing mixture of main fractions of CCP/CSP at various proportions will be prepared with the same procedure as 4.1. Physical properties of the coconut milk model systems will be determined by method used in 4.1 and compared with the standard coconut milk model system. The adequate proportion of main fraction of CCP/CSP that gives the highest stability will be chosen for further study in section 4.2 (3).

(3) The coconut milk model system containing a proportion of CCP/CSP chosen from the 4.2 (2) will be prepared in various total protein concentration. Physical properties of the coconut milk model system will then be determined by the same method in 4.1 in comparison with the standard coconut milk model system. The total protein concentration level that gives the highest stability will be chosen for study in section 4.3.

4.3 Effects of heat treatment at various levels on emulsion stability of coconut milk in model system

5. Experimental Design and Statistical Analysis All analysis and measurement will be performed in at least three replicates. The experimental design for section 3.2 and 4 will be a completely randomized design (CRD). Data will be analyzed by the analysis of variance (ANOVA) and mean comparison will be carried out by Duncan’s multiple-range test at P < 0.05 using SPSS software version 10.0.

Expected outcome • The first part of the project will provide information about types, proportion and characteristics of proteins in coconut meat and coconut milk. It will be used to design a model system of coconut milk for investigating coconut proteins on emulsion stability of coconut milk. • The important functional properties of major protein fractions will be obtained from the second part of the experiment. The information will indicate the potential use of coconut proteins as a new functional ingredient in food industry.

Expected outcome (cont.) • In the last part, role of coconut proteins (type, proportion and concentration) on stability of fresh and thermal processed coconut milk will be revealed. The knowledge gained is expected to be useful as a direction for development of stable thermally processed coconut milk products.

6. Research plan

Thank you

Mr. Ekasit Onsaard 4483011