Crop Science and Production Collection

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Browsing Crop Science and Production Collection by Author "Chaula, Davis"

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    Effect of final moisture content, cooling time and paddy variety on milling quality of rice (Oryza sativa, L.)
    (Pearl Research Journals, 2016) Furahisha, Kulwa; Chove, Lucy Mlipano; Chaula, Davis
    The study was carried out to establish the effects of three factors -final moisture content (FMC), shade-cooling time (CT) and paddy variety on rice milling quality. Paddy was sun dried to final moisture contents ranging from 9.0 to 15.5% (on wet basis) and shade-cooled for 0, 6, 12, 18, and 24 h at ambient temperature (27.20 to 35.10 o C). Five paddy varieties, TXD 88, TXD 306, SUPA, IRRITA 1, and IRRITA 2 were studied. The milling tests were carried out using a laboratory rice mill. Latin square design with 5 replications (5x5 orders) was used. Physical properties and milling quality in terms of total rice yield (TRY), head rice yield (HRY) and whiteness index (WI) were analyzed. The physical properties differed significantly (P<0.05) among varieties. SUPA had good size, shape and chalkiness whereas TXD 88 had poor quality for all these parameters. IRRITA 1 and IRRITA 2 produced higher TRY compared to other tested varieties. TXD 88 had higher whiteness index but lower HRY compared to other tested varieties. Higher yields, which were significantly different for TRY and HRY (P<0.05) were obtained at moisture content between 9.0 to 12.5% for TRY, but between 10.5 to 14.0% for HRY
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    Fatty acid profiles and lipid oxidation status of sun dried, deep fried, and smoked sardine (Rastrineobola argentea) from Lake Victoria, Tanzania
    (Taylor & Francis, 2019) Chaula, Davis; Laswai, Henry; Chove, Bernard; Dalsgaard, Anders; Mdegela, Robinson; Hyldig, Grethe
    Freshwater fishes contain long chain omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) of highest nutritional value. PUFAs in fish are susceptible to oxidative damage during processing and subsequent storage. Sardines (Rastrineobola argentea) are an important fish species of Lake Victoria, constitut- ing 72.3% of the total landings by weight on the Tanzanian side of the lake. Fatty acid profiles and lipid oxidation status of sun-dried, deep-fried, and smoked sardines were investigated. Lipid oxidation was assessed by peroxide value, thiobarbituric acid reactive substances (TBARS), and free fatty acids. Fatty acids were analyzed by gas chromatography with flame ionization detector. The three omega-3 PUFAs: docosahexaenoic acid (C22:6n-3), docosapentaenoic acid (C22:5n-3), and eicosapentaenoic acid (C20: 5n-3) contributed 57–60, 63, and 38% of PUFAs in sun-dried, smoked, and deep-fried sardines, respectively. Lipid oxidation reactions were more pronounced in sardines dried on sand and rocks, with TBARS values 97.87 and 84.18 μmolMDA/kg, respectively. The polyene index was significantly lower (p < 0.05) in deep-fried sardines, indicating lower retention of PUFAs in the product. Lake Victoria sardines are a rich source of omega-3 PUFAs. PUFAs in sun-dried sardines are prone to oxidative damage. Smoking resulted in relatively higher retention of omega-3 fatty acids in products.
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    In situ pectin engineering as a tool to tailor the consistency and syneresis of carrot purée
    (Elsevier, 2012) Christiaens, Stefanie; Buggenhout, Sandy Van; Chaula, Davis; Moelants, Katlijn; David, Charlotte C.; Hofkens, Johan; Loey, Ann M. Van; Hendrickx, Marc E.
    To investigate whether in situ pectin engineering would be a helpful tool in tailoring the consistency and syneresis of vegetable purées, carrot was selected as a plant tissue in which the textural properties are largely influenced by pectin methylesterase-induced pectin changes. The effect of low-temperature and high-temperature blanching, as well as the effect of two types of mechanical disruption, blending and high-pressure homogenisation, on the flow properties of carrot purée was explored. The influence of these different purée preparation steps on pectin was examined via physicochemical analysis of fractionated walls and isolated polymers, and via anti-pectin antibodies entailing in situ and ex situ analyses. Purée prepared by blending non-pretreated carrots showed a rather high consistency and pronounced syneresis. Treatments that solubilise pectin, such as high-pressure homogenisation and, in particular, high-temperature blanching, limited syneresis phenomena. In contrast, when the intercellular adhesion in carrot tissue was strengthened via low-temperature blanching, the degree of syneresis increased. High-pressure homogenisation was useful to reduce the carrot tissue particle size and, consequently, resulted in a lower consistency carrot purée. Low-temperature blanching on the other hand increased the consistency of carrot purée as the higher level of intercellular adhesion presumably led to an increased resistance to particle disintegration upon blending or high-pressure homogenisation