Discrimination of pomegranate fruit at different harvest dates by instrumental and sensory measurements in consideration of long supply chains

摘要

Investigation of harvest maturity indicators for pomegranate ('Bhagwa') in consideration of long supply chains was conducted. Fruit were harvested at three different maturities along days after full bloom (DAFB); Harvest 1 (HI) at 157 DAFB, H2 at 167 DAFB, and H3 at 175 DAFB. Fruit quality during a 6-week simulated shipping period at 5°C with 95% RH and subsequent five days of shelf life at 20°C with 75% RH were investigated. Instrumental evaluation of aril colour, juice content, juice absorbance (520nm), total soluble solids (TSS), pH, titratable acids (TA), and phytochemicai components including total phenolics, flavonoids, and anthocyanins were carried out. In addition, textural properties of arils which included hardness, toughness, bioyield point, and Young's modulus were also investigated. During the shelf life period, individual fruit were rated by a trained sensory panel based on appearance, taste, and texture. Relationships between the instrumental and descriptive sensory data were explored for harvest maturity determinants using discriminant analysis. Among the attributes evaluated, TSS, juice content, aril hardness and anthocyanin content were the most decisive attributes distinguishing the harvest maturities investigated. The results showed that to ensure acceptable quality of'Bhagwa', harvest time should be between 167-175 DAFB (H2 and H3) when fruit had reached maximum TSS level (>16 °Brix; H3) and juice content (>65 mL 100 g1 aril; H2). In addition, discriminant analysis (DA) showed the possibility of combining these decisive harvest parameters with aril red colour intensity. The harvest index proposed in this study could be used as a guide to establish a reliable harvest maturity index to assist in assuring fruit quality in consideration of long supply chains for the investigated cultivar.