Calyx Detaching Force of Strawberry

Studies on Saving of Calyx Removing Labor of Strawberry for Processing (Part I)

Abstract

Calyx detaching from strawberry fruits requires much labor at the beginning of processing. With the purpose to breed new varieties of strawberry with calyx easily removable by slight power, some factors which affect on the detachability of calyxes were investigated employing an instrument for measuring the force for detaching. The instrument was devised combining a 2kg automatic weighing machine with a stop indicator, a fruit fixing fitting and pulling device. Calyx detaching force was found to relate to the shape of the fruit to be measured. The force for necked fruits or for small fruits was lower than for no neck fruits or for large fruits. The force was also different among varieties of the employed strawberry. The force for wild species was below 100g, that for var. America for processing was 300 to 400g, and more 500g for table strawberries. As the ripening proceeded, the calyx detaching force decreased and it was found that the amount and quality of pectin change in different patterns between calyx and pith around the part where the calyx was torn off.