Research - Kiwi Fruit
Variation in Gastric pH May Determine Kiwifruit’s Effect on Functional GI Disorder: An in Vitro Study
Bruce Donaldson 1,* , Elaine Rush 1, Owen Young 1 and Ray Winger
Consumption of kiwifruit is reported to relieve symptoms of functional gastrointestinal (GI) disorder. The effect may be related to the proteases in kiwifruit. This in vitro study aimed to measure protein hydrolysis due to kiwifruit protease under gastric and duodenal conditions. A sequence of experiments incubated meat protein, with and without kiwifruit, with varying concentrations of pepsin and hydrochloric acid, at 37 °C for 60 min over the pH range 1.3–6.2 to simulate gastric digestion. Duodenal digestion was simulated by a further 120 min incubation at pH 6.4. Protein digestion efficiency was determined by comparing Kjeldahl nitrogen in pre- and post-digests. Where acid and pepsin concentrations were optimal for peptic digestion, hydrolysis was 80% effective and addition of kiwifruit made little difference. When pH was increased to 3.1 and pepsin activity reduced, hydrolysis decreased by 75%; addition of kiwifruit to this milieu more than doubled protein hydrolysis. This in vitro study has shown, when gastric pH is elevated, the addition of kiwifruit can double the rate of hydrolysis of meat protein. This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate of protein hydrolysis, which may explain how kiwifruit relieves functional GI disorder.
Source : Journal Nutrients
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Mood improvement in young adult males following supplementation with gold kiwifruit, a high-vitamin C food
Anitra C. Carr*, Stephanie M. Bozonet, Juliet M. Pullar and Margreet C. M. Vissers
Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, PO Box 4345, Christchurch 8140, New Zealand
Enhanced intakes of fruit and vegetables have been associated with improved psychological well-being. We investigated the potential mood-enhancing effects of kiwifruit, a fruit rich in vitamin C and a number of other important micronutrients. Young adult males (n35) were supplemented with either half or two kiwifruit/d for 6 weeks. Profile of Mood States questionnaires were completed at baseline and following the intervention. No effect on overall mood was observed in the half a kiwifruit/d group; however, a 35 % (P=0·06) trend towards a decrease in total mood disturbance and a 32 % (P=0·063)trend towards a decrease in depression were observed in the two kiwifruit/d group. Subgroup analysis indicated that participants with higher baseline mood disturbance exhibited a significant 38 % (P=0·029) decrease in total mood disturbance, as well as a 38 % (P=0·048) decrease in fatigue, 31 % (P=0·024)increase in vigour and a 34 % (P=0·075) trend towards a decrease in depression, following supplementation with two kiwifruit/d. There was no effect of two kiwifruit/d on the mood scores of participants with lower baseline mood disturbance. Dietary intakes and body status of specific micronutrients indicated a significant increase in the participants’ vitamin C intakes and corresponding plasma levels of the vitamin. The results indicate that enhanced intake of kiwifruit by individuals with moderate mood disturbance can improve overall mood.
Source : Journal of Nutritional Science
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