Antioxidant activity of different extracts of red pitaya (Hylocereus polyrhizus) seed

Antioxidant activity of three different extracts (ethanolic, chloroformic, and hexanic) of red flesh pitaya (Hylocereus polyrhizus) seed using free radical scavenging assay, linoleic acid model system, and ferric thiocyanate (FTC) method was determined. Ethanolic extract inhibit 74.76% of free radicals at 1000 μg/mL, while chloroformic extract gave the highest inhibition using linoleic acid model system (98.90% at 100 μg/mL) and FTC (96.34%) method. Total phenolic and ascorbic acid contents of the seed were 13.56 ± 2.04 and 0.36 ± 0.01 mg/g, respectively, while catechin was the major flavonoid detected. In conclusion, the study showed that both polar and non-polar compounds contribute to the antioxidative activity measured

Effect of boiling and stir frying on total phenolics, carotenoids and radical scavenging activity of pumpkin (Cucurbita moschato)

Effect of various cooking methods on antioxidant content and radical scavenging activity of pumpkin was evaluated. Pumpkin (Cucurbita moschata) was boiled and stir-fried for 2, 4 and 6 minutes respectively. Beta-carotene and lycopene were determined using HPLC and total phenolics measured using Folin-Ciocalteu method. The free radical scavenging activity of the samples was determined using 1, 1-diphenyl-2-picrylhydrazyl assay. Interestingly, result of the study showed an increase in both beta-carotene (2 to 4 times) and lycopene (17 to 40 times) content of pumpkin after cooking for 2, 4 and 6 minutes. However, the treatment resulted in 18 to 54% losses of total phenolics content of the pumpkin. Nevertheless, the free radical scavenging activity exhibited by cooked pumpkins was found to be high, in the range of 81.1% to 94.6% with IC50 of 1.41 to 1.62mg ml-1

Effects of different levels of preharvest shading on the storage quality of strawberry (Fragariax ananassaDuchesne) cv. Ostara II. chemical characteristics

To study the effects of different levels of preharvest shading (74, 58, 48, 38 and 5% of light penetration which were denoted by So' SI' S2' 53 and S4 respectively) on developing strawberry (Fragaria X ananassa Duchesne) cv. Ostara fruits, some chemical tests (pH, total soluble solids and titratable acidity) associated with fruit quality were carried out. Results showed that although the different levels of preharvest shading were found to demonstrate a significant effect on the chemical parameters studied, this could only be detected in fruits shaded by S4 and S3. However, for total soluble solids, significant interactions were observed between location of fruit and fruit type and also between storage day and fruit type

Post-harvest Storage of Guava (Psidium guajava, L, var. Taiwan)

Guava fruit (var. Taiwan) were stored at room temperature (26°C), 200e and 50 e and the characteristics of the fruits during storage were evaluated. Guava fruit has a post-harvest life of about 1 week during room temperature storage and post-harvest life can be extended by a few days during storage at 20°C. At 2~ eand 200 e, post-harvest life is limited by the occurrence of rots. At~e, bronzing of the guava skin occurs at about 2 weeks of storage. Rots were not evident during storage at 5°e. The average pH, total soluble solids and titratable acidity of guava at harvest was 3.5,5.4°Brix and 62.8 ml O.lNaOH/ 100g respectively. The levels of individual soluble sugars were: fructose 1.60 g/100g, glucose 1.06g/1 OOg and sucrose O. 78g/1 OOg at the commencement of the study. There were significant increases in total soluble solids during storage at all temperatures. Titratable acidity did not change significantly during storage for 10 days at room temperature and 200 e and during storage for 4 weeks at 5° e. There were significant increases in fructose, glucose and total soluble sugars but no significant differences in sucrose levels during storage at room temperature. Significant increase in fructose levels and total soluble sugar levels were also obtained during storage at 200 e and 5°e. The fructose/glucose ratios significantly increased during storage at all temperatures

Effects of sifferent levels of preharvest shading on the storage quality of strawberry (Fragariax ananassa Duchesne) cv. Ostara I. physical characteristics

The effects of shading developing fruits up to harvest on strawberry (Fragaria X ananassa Duchesne) cv. 'Ostara ' fruit quality were studied. Plants were shaded with netting of different levels of light penetration (74,58, 48,38 and 5% which are denoted by S(J SJ' S2' S3 and S4 respectively). Results showed that effects could only be detected when plants were subjected to a very low level of light intensity, S4 . Location of fruits on the plant affected the fresh fruit weight, surface glossiness and fruit firmness significantly. Fruits shaded by leaves were heavier and able to retain surface glossiness longer than exposed fruits

Antioxidative activities of chromatographic fractions obtained from root, fruit and leaf of Mengkudu (Morinda citrifolia L.)

Crude extracts of root, leaf and fruit of Morinda citrifolia were fractionated on a Sephadex LH-20 column with ethanol as eluate. Based on UV absorption intensity of phenolic compound (725 mm) the Sephadex LH-20 column was able to separate fruit, leaf and root extracts into six, five and five fractions, respectively. The results showed that all the fractions tested exhibited considerably high antioxidative activity in the ferric thiocyanate assay and thiobarbituric acid test and the activities of some of the fractions were as good as those of either tocopherol or BHT. The fractions from different parts of the plants were found to contain different amounts of total phenolic compounds, which, interestingly, do not correspond to the antioxidative activity measured. This is probably due to the presence of different phenolics in the samples, with different antioxidative activities which involves various mechanisms inhibiting the oxidation process. The study suggested that root, leaf and fruit of M. citrifolia might contribute significantly to exogenous antioxidant which is crucial in combating oxidative stress

Preliminary study of the chemical composition of rice milling fractions stabilized by microwave heating

The present paper presents a preliminary study of the chemical composition of local stabilized rice bran. The four rice-bran milling fractions, after stabilization by microwave heating on site at the rice mill, were analyzed for their chemical composition. The content of all fractions tested (in g/100 g) consisted of 8.7–18.9 fat, 8.8–15.2 protein, 8.5–12.6 moisture, 4.2–7.7 ash, 22.2–44.8 total carbohydrates (by difference) and 18.3–30.5 total dietary fibre. It is encouraging to note that total phenolic compounds of all fractions were detected at 257–488 mg ferulic acid equivalent per 100 kg, while carotenoid contents were found to be in the range of 58.7–216 μg/100 g. The amino acid composition varied within wide limits with proline, histidine and threonine as the amino acids. Higher concentrations of amino acids found (in decreasing order) were arginine, glutamic acid, aspartic acid and serine. Phosphorus and potassium were among the major mineral constituents of rice bran, with values up to 1633 mg/100 g. The first rice bran fraction was found to be highest in energy, fat and minerals and could be a very good source of dietary fiber and other nutrients

Inhibitory effect of Morinda citrifolia L. on lipoprotein lipase activity.

Efficacy of Morinda citrifolia L. leaf (MLE) and fruit extracts (MFE) in inhibiting lipoprotein lipase (LPL) was determined in vitro. The result of the study showed that the highest inhibition on the LPL activity was exhibited by MLE (66%± 2.1%), which is significantly higher than that demonstrated by MFE (54.5%± 2.5%), green tea extract (GTE) (54.5%± 2.6%), and catechin (43.6%± 6.1%). Percent of LPL inhibition increase with concentration of the extracts. Quantitative analysis of the extracts revealed the presence of high levels of (+)−catechin at 63.5 ± 17 and 53.7 ± 5.7 mg/g in MLE and MFE, respectively, although not as high as that found in GTE (530.6 ± 42 mg/g). Appreciable amount of epicatechin was found in all extracts tested, while rutin was only found in MLE and MFE. The study suggested that both leaf and fruit of M. citrifolia may be used as antiobesity agents in body weight management

Fruits: nutritious, colourful, yet fragile gifts of nature

Fruits, which are consumed because of their excellent taste and health benefits, mainly contribute carbohydrate, dietary fibre, vitamins and minerals to balance the human diet. Fruits have been a part of the human diet since the dawn of history but their nutritional importance has only been recognised in recent times. Commerce in fruits began in the 1980’s when awareness on their nutritional importance has risen. Since then, its demand in the international markets has also increased tremendously. Hence, many tropical countries have moved from small, scattered farms to large commercial fruit plantations. Malaysia went through a series of phases since the inception of the National Agricultural Policy in 1984 to develop its fruit industry to reach its present status- able to be a leading exporter of some tropical fruits. It is not possible to improve the quality of fruits once the fruits harvested but they can be preserved by slowing down the rate of undesirable changes, which leads to a reduction in their quality. Postharvest qualities of fruits are affected by pre-harvest factors, stage of maturity at harvest and postharvest factors. This is due to the fact that there are many physico-chemical changes taking place during growth, maturation, ripening and senescence stages in the life span of the fruit. A range of environmental conditions such as temperature, relative humidity, atmospheric compositions and mechanical injury can influence the rate at which these changes occur in harvested fruits. All these can be manipulated by careful management of the postharvest handling system for maintenance of quality and extension of shelf life of the fruits. Proper postharvest handling practices are essential to reduce postharvest losses and maintain overall quality of fruits after harvest. Human factors such as handling practices and attitudes, and technical aspects such as improper infrastructure and handling techniques could contribute to these losses. Due to change in the life style especially in urban areas, convenient and ready-to-eat fresh-cut fruits, which is also referred to as minimally processed fruits are becoming more popular in the last two decades. However, there are problems associated to it. Hence, studies were conducted to overcome these problems. Apart from the increasing demands for fresh-cut fruits, there is also a trend during the same period of time, where consumers consume fruits not only for its nutritional contents but emphasis is also given to its functional properties. The way forward for the fruit industry globally, including Malaysia, is to develop technology both for whole, intact and minimally processed fruits for shelf-life extension and quality maintenance not only from the perspective of nutritional aspects but also to give emphasis on the stability of the functional properties when they are being subjected to the different postharvest technologies at different stages of the distribution chains (whole, intact fruits) and preparation (minimally processed fruits)

Fruits: importance of preharvest factors, maturity stage at harvest & postharvest treatments

Fruits have been part of the human diet since the dawn of history but their nutritional importance has only been recognised in recent times. Commerce in fruits began in the 1980’s when awareness on their nutritional importance has risen. Since then, its demand in the international markets has also increased tremendously. Malaysia went through a series of phases to develop its fruit industry to reach its present status- able to be leading exporter of some tropical fruits. Quality of fruits could not be improved once harvested but it can be preserved by slowing down the rate of undesirable changes which leads to a reduction in their quality. Postharvest qualities of fruits are affected by pre-harvest factors, stage of maturity at harvest and postharvest factors because of the many physico-chemical changes taking place during the life span of the fruit. The rate at which these changes occur can be manipulated by careful management of the postharvest handling system for quality maintenance and shelf-life extension of the fruits. Due to changes in consumers’ life style especially in urban areas, convenient and ready-to-eat fresh-cut fruits are becoming more popular in the last few decades. However, there are problems associated to it which requires studies to be carried out to overcome them. Apart from the increasing demands for these fresh cut fruits, there is also a trend during the same period of time, where consumers consume fruits not only for its nutritional contents but emphasis is also given to its functional properties