Browsing by Author "Hailu, Tsegay"

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    Determinations of Optimum Maturity Indices and Storage life for Selected Avocado Cultivars Grown in Wendo-genet (Southern Ethiopia)
    (Addis Ababa University, 2017-07) Hailu, Tsegay; Worku, Teshome( Asst Perofesser)
    This study was conducted to determine the optimum maturity indices and storage life for selected avocado cultivars grown in Wendo-Genet: South Ethiopia. Maturity has a pronounced effect on the physical, nutritional and chemical compositions, and post-harvesting quality attributes of avocado fruit. Avocado fruit quality parameters such as, physico-chemical properties, dry matter and oil content of the mesocarp, and oil characteristics, of Hass and Fuerte avocado cultivars were conducted to determine the optimum maturity indices and acceptable fruit quality. Besides of that the effect of storage temperature on the shelf life, weight loss, and chilling injury of Hass avocado cultivar harvested which stored at 2, 5, 8 and 20 oC for 7, 14, 21 and 28 days was investigated. Fuerte and Hass avocado cultivars were harvested at their early, middle and late harvesting period in 2017 from Wendo-Genet Agricultural Research Center (March to May at one-month intervals). Statistically, significant differences between the avocado cultivars were observed in terms of fruit weight, percent of pulp to whole fruit weight ratio, pulp and seed weight during the harvesting season (March to May). Both dry matter and oil content of both cultivars increased significantly (p < 0:05) with harvesting time of the fruits. Dry matter of Hass and Fuerte avocado fruits gradually increased from 17.89 ± 2.36 to 29.11 ± 2.27% and 18.22 ± 1.811 to 28.73 ± 1.88%, respectively, from March to May. Similarly, oil content of Hass and Fuerte avocado fruits gradually increased from 6.66± 0.1 to 19.21±1.00 respectively. Avocado oil characteristics: oil content, acid value, peroxide value, and free fatty acid value of the two avocado cultivars at different harvesting time were examined. The oil characteristics result showed that both avocado cultivars harvested in March, April and May were within the range for acceptable condition for consumers as reported by different authors except for the free fatty acid which was slightly higher. Inter-cultivar differences of total soluble solids, and weight loss were found to be significantly different as the harvesting period goes from March to May while pH value showed insignificant difference among the cultivars. The storage experiment revealed that storage temperature affected the shelf life and quality of Hass avocados. Hass avocado fruit stored at 5 oC for 4 weeks had longer shelf life with medium chilling injury than the fruit stored at 2 oC which showed high chilling injury within 3 weeks storage time. The fruit stored at 8 oC and 20 oC had shorter shelf life, developed browning mesocarp, and rapidly ripened in short time. Storage at ambient temperature (20°C) resulted in high weight loss as compared to 2 and 5 °C storage temperatures due to increasing respiration rate and transportations of water from the fruit to the environment at higher temperature. As a result of this study; the optimum harvesting period of Hass and Fuerte cultivar were determined to be in April in terms of fruit dry matter 22.827%and 22.7.0 % and oil content 11.43% and 14.53% respectively for the cultivars. The storage of Hass avocado at 5°C for 4 weeks was the optimum storage condition causing less chilling injury and weight loss and maintaining better fruit quality. Keywords: Avocado (persea americana Mill.), Maturity indices, fruit quality, oil characteristics, storage, harvesting period.