Research Articles (Food Science)

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    Fatty acid composition, bioactive phytochemicals, antioxidant properties and oxidative stability of edible fruit seed oil : effect of preharvest and processing factors
    (Elsevier, 2020-09) Kaseke, Tafadzwa; Opara, Umezuruike Linus; Fawole, Olaniyi Amos
    Fruit seed is a by-product of fruit processing into juice and other products. Despite being treated as waste, fruit seed contains oil with health benefits comparable or even higher than the conventional seed oil from field crops. In addition to essential fatty acids, the fruit seed oil is a rich source of bioactive compounds such as tocopherols, carotenoids, flavonoids, phenolic acids and phytosterols, which have been implicated in the prevention of chronic and degenerative diseases such as cancer, diabetes and cardiovascular diseases. The emerging potential of fruit seed oil application in food and nutraceuticals has prompted researchers to study the effect of preharvest and processing factors on the seed oil quality with respect to nutritional qualities, antioxidant compounds and properties. Herein, the effect of cultivar, fruit-growing region, seeds pretreatment, seeds drying and seed oil extraction on tocopherols, polyphenols, phytosterols, carotenoids, fatty acids, antioxidant activity and oxidative stability of the fruit seed oil is critically discussed. Understanding the influence of these factors on seed oil bioactive phytochemicals, nutritional qualities and antioxidant properties is critical not only for genetically improving the oilseeds plants with desired characteristics, but also in seed oil processing and value addition. Therefore, preharvest and processing factors are essential considerations when determining the application of fruit seed oil.
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    Harvest and postharvest factors affecting bruise damage of fresh fruits
    (KeAi Communications Co., Ltd., 2019) Hussein, Zaharan; Fawole, Olaniyi A.; Opara, Umezuruike Linus
    Fresh fruits are susceptible to bruising, a common type of mechanical damage during harvest and at all stages of postharvest handling. In quest of developing and adoption of strategies to reduce bruise damage, it is of utmost importance to understand major factors influencing bruise susceptibility of fresh produce at these stages. This review presents a critical discussion of factors affecting bruising during harvest and postharvest handling of fresh fruits. Excessive compression forces during harvesting by handpicking or machines, and a series of impacts during harvesting, transport and packhouse operations can cause severe bruise damage. The review has further revealed that bruising is dependent on a number of other factors such as produce maturity, ripening, harvest time (during the day or season) and time lapse after harvest. The susceptibility to bruising is partly dependent on how these factors alter the produce physiological and biochemical properties, and the environmental conditions such as temperature, humidity and several other postharvest treatments. Hence, the successful applications of harvesting techniques by use of trained personnel and proper harvesting equipment are essential to reduce both the incidence and severity of bruising. Furthermore, the careful selection of postharvest handling temperature and other treatments can increase resistance of fresh produce to bruise damage.
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    Postharvest physiological responses of pomegranate fruit (cv. Wonderful) to exogenous putrescine treatment and effects on physico-chemical and phytochemical properties
    (Elsevier, 2020-02-28) Fawole, Olaniyi Amos; Atukuri, Julian; Arendse, Ebrahiema; Opara, Umezuruike Obia
    Pomegranate fruit (cv. Wonderful) were treated with putrescine (1, 2 and 3 mmol/L) before storage for 4 months at 5 °C and 95 % RH and the effects on postharvest life and quality attributes were studied. Results showed that incidence of physiological disorders such as external decay, husk scald, chilling injury and aril browning increased with progressive storage but treating pomegranate fruit with putrescine reduced incidence of most disorders. Control fruit had higher levels of external decay (1.72 %–33.26 %), chilling injury (10.53 %–38.77 %) and scalding (15.04 %–100 %) with less attractive color during 4 month storage. Variations were observed on other fruit quality parameters although treatment with putrescine at 2 and 3 mmol/L concentration reduced changes in color, total soluble solid, Titratable acidity and ascorbic acid. Sensory parameters were best preserved in fruit treated with 2 mmol/L concentration of putrescine with respect to juiciness and crispness. Treatment of pomegranate fruit with putrescine resulted in improved storability and fruit quality during storage. Therefore, for short term storage, 2 mmol/L concentration of putrescine could be recommended for maintaining fruit quality especially in the first two months of storage. However, for longer storage period, a higher concentration is recommended, as 3 mmol/L concentration was the most effective in alleviating disorders and maintaining physico-chemical parameters and sensory attributes during storage in this study.
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    Effects of honeybush (Cyclopia subternata) extract on physico-chemical, oxidative and sensory traits of typical Italian salami
    (Wiley, 2020-02-18) Smit, Paula; Cullere, Marco; Zotte, Antonella Dalle; Balzan, Stefania; Hoffman, Louwrens Christiaan; Novelli, Enrico
    Honeybush (Cyclopia subternata Vogel) is an indigenous South African shrub enjoyed as hot brewed tea. "Unfermented" honeybush is also a potential antioxidant bioactive extract for foodstuffs due to its polyphenol content. The effect of "unfermented" honeybush extract (Hob; 0.5%) was evaluated in typical Italian salami and compared with nitrate (Nit; 100 mg/kg) and a control (Ctl; without nitrate or honeybush). After 35 days of ripening, Hob had a higher (p < .01) water activity (0.928), compared with Ctl (0.923) and Nit (0.924). Final pH (5.35-5.24) was not affected by treatments. Lower lipid oxidation was observed in Hob and Nit treatments (p < .001) compared with Ctl. Internal color and odor intensity were similar among treatments. Salami with honeybush extract had less spontaneous outer surface mold growth whereas the Ctl showed intermediate growth (p < .05). Honeybush extract seems a promising natural ingredient with antioxidant action.
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    Advances in design and performance evaluation of fresh fruit ventilated distribution packaging : a review
    (Publishers version, 2020-02-17) Mukama, Matia; Ambaw, Alemayehu; Opara, Umezuruike Linus
    This review was initiated to realise the state-of-the art in optimising the ventilation and structural requirements of corrugated packaging carton design. Researchers have been using computational methods: computational fluid dynamics, particularly, the finite volume method, to analyse the airflow and heat transfer performances, and computational structural dynamics, particularly, the finite element method, to analyse the loss of compression strength due to vent-holes. Models are validated using actual testing: wind tunnel based forced air cooling system to study the produce cooling kinetics and box compression test machine for the package industry to study the structural dynamics. Studies on the rate and uniformity of produce cooling and the loss of structural strength in corrugated cartons as a function of size, shape, and location of vent-holes are reviewed. Based on experimental data, results show that the loss in strength can range between 10–40 % on addition of vent and hand holes on cartons, and reasonable increase in cooling rates is only achieved with increase in carton face ventilation area only up to 7–8 %. With regards to internal packaging components, increasing awareness of consumers to the environmental degradation of especially disposable plastic packaging means packers and suppliers must devise means to cut back and eventually eliminate plastic packaging from fruit and vegetables.