Partial characterization of miracle fruit (Synsepalum dulcificum Daniell) and determination of miraculin, a taste modifying glycoprotein

Date

10-2009

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Veronica P. Migo

Co-adviser

Susana M. Mercado

Abstract

PEREZ, SWEEDY KAY LINDAYEN. College of Arts and Sciences, University of the Philippines Los Banos. October 2009. Partial Characterization of Miracle Fruit (Synsepalum dulcificum Daniell) and Determination of Miraculin, A Taste-Modifying Glycoprotein.

Advisers: Dr. Veronica P. Migo and Dr. Susan M. Mercado

Miracle fruit (Synsepalum dulcificum Daniell) is a shrub or small tree which belongs to the Sapotaceae family and was first found in its native land, West Africa. The fruit is known for its unusual characteristic of modifying sour taste into sweet taste after the mouth has been exposed to its mucilaginous pulp. It is a tropical fruit which grows also in the Philippines.

Preliminary characterization of miracle fruit was done which includes proximate analysis, determination of vitamins A and C, mineral, carbohydrate content and monosaccharide composition. The miracle fruit pulp with skin contains 76.26% moisture, 6.19% crude protein, 1.37% crude fat, 2.38% crude fiber and 0.82% ash. On a moisture-free basis, the obtained % crude protein was 26.07%. The mineral composition of the fruit pulp with skin was determined by atomic absorption spectrophotometry for Na, K, Ca, Mg, Fe, Mn, Cu, P, and heavy metals such as Pb, Cr, and Cd. Total phosphorus content was analyzed by the phosphomolybdate method. It was observed that the most abundant mineral in the miracle fruit pulp was calcium at a concentration of 281.4 ppm, followed by magnesium, 247.7 ppm. Phosphorus content was relatively low at 264.8 ppm. Also, only trace amounts of Na, Cu, Cr, Fe, Mn and Cd were obtained. No lead was detected. Carbohydrate analysis was done to determine the total sugars using the phenol-sulfuric method and total reducing sugars by the DNS method. Miracle fruit pulp contains 37.91 % total sugars and 8.50 % total reducing sugars on a moisture-free basis.

Vitamin A content of miracle fruit was not detected (d1 = 4.0 IU/g). Vitamin C analysis (Ascorbic acid) gave a value of 240.05 mg/kg.

Isolation of the taste-modifying glycoprotein, miraculin, was done by extracting the fruit pulp with 0.5 M NaC1, followed by fractionation with ammonium sulfate at 50 % saturation. The ammonium sulfate supernatant was dialyzed. Purification was done using CM-Sephadex ion-exchange column chromatography. Three bands were observed in native gel electrophoresis corresponding to molecular weights of 59.3, 52.3 and 27.9 kDa suggesting that the protein isolate obtained still needs further purification.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2009 C4 P47

Document Type

Thesis

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