Analysis of aroma compounds and nutrient contents of mabolo (Diospyros blancoi A. DC.), an ethnobotanical fruit of Austronesian Taiwan

AbstractDiospyros blancoi A. DC. is an evergreen tree species of high-quality wood. Mabolo, the fruit of this plant, is popular among the natives in Taiwan, but its potential in economic use has not been fully explored. Mabolo has a rich aroma. Of the 39 different volatile compounds isolated, its intact fruit and peel were found to both contain 24 compounds, whereas the pulp contained 28 compounds. The most important aroma compounds were esters and α-farnesene. Our data show that mabolo is rich in dietary fiber (3.2%), and the contents of other nutrients such as malic acid, vitamin B2, vitamin B3, folic acid, pantothenic acid, and choline chloride were 227.1 mg/100 g, 0.075 mg/100 g, 0.157 mg/100 g, 0.623 mg/100 g, 0.19 mg/100 g, and 62.52 mg/100 g, respectively. Moreover, it is rich in calcium and zinc; the contents of which were found to be 42.8 mg/100 g and 3.6 mg/100 g, respectively. Our results show that D. blancoi has the potential to be bred for a novel fruit

Effect of shaking process on correlations between catechins and volatiles in oolong tea

Shaking the tea leaves is the key manipulation to making oolong tea. It contributes to the formation of flavor and fragrance in oolong tea. The dynamic variations of catechins and volatile organic compounds (VOCs) during the shaking process were investigated. The results showed that the contents of epicatechin, epigallocatechin, epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) first decreased after the shaking and then increased to the initial value before the next shaking. Geraniol, linalool and its oxides, and phenylethyl alcohol showed similar variations. The contents of trans-β-ocimene, 1H-indole, and 3-hexenyl hexanoate increased after the second or third shaking (the late fermentation stage). However, the contents of aldehydes showed an opposite trend to other VOCs. The abundance of phenylethyl alcohol was positively related to the content of ECG and EGCG ​during fermentation, whereas the abundance of cis-3-hexenal was negatively related to the content of ECG. The correlations between catechin and VOCs indicated that shaking affected the chemical transformation of the compounds in oolong tea

Effects of Epigallocatechin Gallate on the Stability of Epicatechin in a Photolytic Process

Catechins belonging to polyhydroxylated polyphenols are the primary compounds found in green tea. They are associated with many physiological properties. Epicatechin (EC) is a non-gallate-type catechin with four phenolic hydroxyl groups attached. The changes in EC treated with color light illumination in an alkaline condition were investigated by chromatographic and mass analyses in this study. In particular, the superoxide anion radical (O2•−) was investigated during the EC photolytic process. EC is unstable under blue light illumination in an alkaline solution. When EC was treated with blue light illumination in an alkaline solution, O2•− was found to occur via a photosensitive redox reaction. In addition, the generation of monomeric, dimeric, and trimeric compounds is investigated. On the other hand, epigallocatechin gallate (EGCG), which is a gallate-type catechin, is stable under blue light illumination in an alkaline solution. Adding EGCG, during the blue light illumination treatment of EC decreased photolytic formation, suggesting that gallate-type catechins can suppress the photosensitive oxidation of EC. Gallate-type catechins are formed via the esterification of non-gallate-type catechins and gallic acid (GA). The carbonyl group on the gallate moiety of gallate-type catechins appears to exhibit its effect on the stability against the photosensitive oxidation caused by blue light illumination

Effect of Harvest Maturity and Heat Pretreatment on the Quality of Low Temperature Storage Avocados in Taiwan

The present study aimed to find out the effects of different fruit maturities and heat pretreatments before storage on the quality of climacteric avocado fruit during low temperature storage. Two local cultivars, \u27Chanan\u27 and \u27Ching?Jin 2\u27, were chosen to analyze the relationship between the degree of fruit maturity at harvest and the quality of the fruits after low temperature (1℃) storage. Quality changes were observed in terms of color of skin, color of flesh, fruit hardiness, chilling injury and rottenness. Fruits of high maturity at harvest showed better storage quality in the two cultivars. Under the storage temperature of 1 ℃, fruit can be stored for 21 days for \u27Chanan\u27 and for 14 days for \u27Ching?Jin 2\u27 , and retained fully ripening quality after three days of ripening treatment at 21℃. Pretreatments of fruits were conducted by immersion of them in 38℃ water for 5, 15, 30 and 60 minutes to decrease the low temperature injury on avocado during 1℃ storage. The pretreatment for 30 minutes resulted in the optimum quality of \u27Ching?Jin 2\u27 fruit after four?week?storage at 1 ℃. Post?treatment of fruit for six hours under 38 ℃ air is recommended to reduce chilling injury in \u27Chin?Jin 2\u27 avocado before the 1℃ storage. Heat shock protein HSP 70 showed highly negative correlation with the chilling injury of fruit stored at 1 ℃

Observations on Flowering Phenology of Main Avocado (Persea americana Mill.) Cultivars in Taiwan

調查‘嘉選一號’、‘嘉選二號’、‘嘉選三號’、‘嘉選四號’、‘Halemana’、‘Hall’、‘Choquette’、‘紅心細葉’、‘79-6-5-3’共9個台灣主要酪梨栽培品種之花序發育狀態與開花習性。綜合三年之資料顯示，9品種之開花日期約在十二至四月間，可分為早花、中花與晚花等三類型。早花品種為‘嘉選四號’與‘嘉選三號’，於十二月初開花至四月初。中花品種為‘79-6-5-3’、‘嘉選一號’、‘Halemana’，花期由一月底到四月初。晚花品種為‘Hall’、‘嘉選二號’、‘紅心細葉’，花期從二月底到四月中。各品種盛花期約持續1-2個月，開花期間溫度較高會使得盛花期的時間佔總花期的比例降低，且有花期提前結束之現象；晚花品種可能由於花芽形成過程間溫度較高，使得花芽發育較慢，造成花期結束較晚之情形發生。在正常氣候條件下，‘嘉選一號’、‘嘉選二號’和‘Hall’下午開雌花為B型品種外，其餘早上開雌花皆為A型品種。 The flower bud development and flowering behavior of 9 main avocado cultivars (‘CAES 1’, ‘CAES 2’, ‘CAES 3’, ‘CAES 4’, ‘Halemana’, ‘Hall’, ‘Choquette’, ‘Hung Shin Shi Yeh’, ‘79-6-5-3’) in Taiwan were observed for a period of three years. Data showed that total 9 cultivars flowered form December to April and could be divided into early, middle, and late blooming groups. ‘CAES4’ and ‘CAES 3’ are early blooming cultivars and flower from early December to early April. Middle blooming cultivars includes ‘79-6-5-3’、‘CAES 1’ and ‘Halemana’, which flower from late January to early April. ‘CAES 2’, ‘Hung Shin Shi Yeh’ and ‘Choquette’ avocado are late blooming cultivars and flower from late February to mid April. The full-bloom period of 9 cultivars is about 1 to 2 month. Warmer temperature during flowering period may lower the percentage of full-bloomed period and precede the end of flowering period. However, for late blooming cultivars, warmer temperature during flower bud formation may decrease development rate and delay the end of flowering period. In normal conditions, except for ‘CAES 1’, ‘CAES2’, ‘Hall’ avocado which are defined as B type cultivars, others are A type cultivars