Perubahan sifat fizikal dan kimia buah kedondong (spondias cytherea sonnerat) pada tiga tahap kematangan

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Date
2006-06
Authors
Ishak, Siti Aishah
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Abstract
A study on the physical and chemical properties of ambarella fruit ( Spondias cytherea Sonn.) at 3 stages of maturity i.e. green fruit, half-ripe and ripe fruit were carried out. Unripe ambarella of 4.85 em in length and 3.55 em width were acidic with a pH value 3.59. The pH increased to 3.67 and 3.87 in half-ripe and ripe fruit respectively. The increase in pH values were consistent with the reduction in total titratable acid and organic acid contents of the fruit. The 5 types of organic acids were identified in ambarella namely citric acid, ascorbic acid, tartaric acid, succinic acid and oxalic acid. These organic acids decreased with fruit maturity and no citric acid was detected in the ripe fruit. Total sugar contents of ambarella was 2.52-3.23 g/100g with glucose-6-phosphate, glucose and fructose as the main sugars. Sucrose and stachyose made up between 3-8% of the total sugars. The increase in total sugar content with fruit maturity was probably due to starch hydrolysis. The unripe green fruit was juicy and crunchy and a penetration test value of 12.17±0.78 N. Consequence of moisture content decrease in half-ripe and ripe fruit (89%), fruit cell lost turgidity which is also influence forces needed to penetrate ambarella fruit. De-esterification and enzymatic depolimerization of bound cell during fruit ripening produce water soluble pectin which also contribute to fruit tissue softening. Proximate analysis was done to determine crude fiber (2.84-2.91%), fat (0.34-0.53%), protein (1.76- 2.33%) and ash (6.23-6.78%) for all maturity stages. Unripe fruits were green in colour and changed to yellowish when they reach the ripe stage consistent with chlorophyll diminished i.e. 0.56 mg/100g in green fruit to 0.38 mg/100g at ripe stage and !3-carotene accumulation (34.30 !lg/1 OOg at green stage increased to 754.32 !lg/100g in ripe fruit). Minerals present in ambarella include phosphorus (3.93-4.52 g/100g), calcium (29.88-35.05 mg/100g), magnesium (11.76-10.34 mg/1 OOg), natrium (4.13-4.36 mg/1 OOg) and zinc (0.24-0.29 mg/1 DOg). Vitamin C of ambarella reached 30.84 mg/100g and it is posseses high in total dietary fiber (16.93-18.85%). Soluble pectin content increased with maturity stage (1.56 ± 0.06-2.42 ± 0.57 g calcium pektate/100g). Pectin methylesterase enzyme activity increased during ambarella maturation. Total phenolic content were not consistent with maturity of the fruit i.e. 686.50 mg/1 00 gram in green stage, 171.20 mg/100g in half-ripe stage and 338.00 mg/100g in ripe stage. FTIR spectrums showed the existence of functional groups C=O, C-0 and OH contributed to the unique aroma and flavour of ambarella. The main volatile compounds found in ambarella were from alcohol, monoterpene, ester, acid, aldehyde and ketone group.
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Keywords
Sifat fizikal , Kimia buah kedondong , (Spondias cytherea sonnerat)
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