บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

The acoustic impulse-response of apples in relation to the fruit’s position during the test, reduced water loss, and apoplastic acidity

Landahl S. and De Baerdemaeker J.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.118

2004

บทคัดย่อ

The acoustic impulse-response of apples in relation to the fruit’s position during the test, reduced water loss, and apoplastic acidity The fruit and vegetable business has an increasing demand for objective quality testing to ensure reliable and fair evaluation of crops and food safety. Stiffness, measured by means of the non-destructive acoustic impulse-response technique is a known parameter for evaluation food texture.

The objective of this research was to examine possible influences o­n apple stiffness by means of fruit-position, reduced water loss, and apoplastic pH. Regarding fruit-position: apples were either placed o­n soft foam or suspended from a laboratory stand. Other apples were covered with cocoa butter immediately after picking to inhibit water loss and were tested after storage. The MT-firmness and osmotic potentials were measured to monitor the effect of the cocoa butter. The apoplastic fluid was collected as indicator of enzyme activity around the cell walls. In addition to the apoplastic fluid, the water status of the apples was examined during storage. As a result no significant difference was found between impulse-responses of apples measured lying or hanging respectively (t-test > 5%). The deviation of the stiffness values from the water-loss-inhibited apples compared to the control group was significant (t-test < 5%) o­n all five test dates. The firmness was significantly different at the four last test dates. The osmotic potential was significantly different at the last three test dates. The stiffness and apoplastic pH of fresh apples at different maturity stages was approximately constant. However, storage induced a decrease.

It can be concluded that the stiffness of a harvested apple could differ because of the disconnection from the tree and its water supply, but not because of the position during the test. o­n the tree stiffness seems insensitive to changes of fruit. However, in storage an effect of water loss and cell wall changes o­n stiffness is suggested.