Strawberry maturity distinguish based on relationship of extracted colour feature value and the physiologic and biochemical indices

The fruit color has an affinitive relationship with the internal quality, and reflects its maturity. In strawberry harvest or grade system, the strawberry maturity is needed to judge, so it is important to judge the strawberry maturity. In order to confirm the optimum color feature value, this paper took the “Tongziyihao” strawberry for an example, the color values of different maturity were extracted at the 3390lx light intensity by using the image collecting system. Then the physiological and biochemical indices, such as soluble solids content (SSC), titratable acidity (TA), fruit firmness, vitamin C and anthocyanin, were detected. The results show that there are remarkable relationship between the extracted color feature value and the physiological and biochemical indices. a^* value of the strawberry is correlative with SSC, fruit firmness, vitamin C and anthocyanin markedly, S value is correlative with TA markedly. The relationship between Vitamin C and a^* value is most remarkable (R²=0.9807), the next are the relationship between a^* and anthocyanin (R²=0.9532), TA and S(R²=0.9305), fruit firmness and a^*(R²=0.9104), the last one is SSC and a^*(R²=0.6819). In a word, a^* value has the most remarkable relationship with the strawberry physiological and biochemical indices. In the end, having analyzed a^* frequency value of different mature strawberry, the maturity distinguish function was funded. According to this function, the strawberry can be harvested or graded into three maturities.