UBC Theses and Dissertations
Evaluation of breadfruit (Artocarpus altilis and A. altilis X A. mariannensis) as a dietary protein source Liu, Ying
Protein malnutrition is a leading cause of child mortality and chronic development disorders in the tropics. This study evaluated the protein quality of breadfruit using three standards measures: (1) yield of fruit and production of protein, (2) the protein content and amino acid profile, and (3) the protein digestibility/amino acid availability. I analyzed field data collected from 2006 to 2012 from 24 breadfruit cultivars in National Tropical Botanical Garden in Kauai, Hawaii. Based on a plant density of 100 trees/ha, breadfruit can yield 10-14 tons of fruit/ha. The commercial cultivar Ma’afala can produce up to 0.52 t/ha of protein. This is higher than wheat, rice, cassava, and potato. To determine the quality of breadfruit protein, I conducted an amino acid analysis of 49 breadfruit cultivars using high performance liquid chromatography with fluorescence detection and determined that the full spectrum of the essential amino acids were present in all cultivars. Breadfruit is especially rich in phenylalanine, leucine, isoleucine, and valine. Ma’afala contained a higher total essential amino acid content than many other staples including wheat, corn, rice, soybean, and yellow pea. To determine breadfruit protein digestibility, I developed a human digestion model, and found that Ma’afala protein was 10-25% more digestible than wheat protein. Ma’afala and wheat protein were compared using a human intestinal epithelial cell model. The results showed that Ma’afala induced similar impact on cell morphology and cytokine production in the model. To determine the overall effect on health, I compared breadfruit and wheat diet in a standard rodent model. The results show that the breadfruit diet did not induce any adverse effects on the overall health or growth of the mice. Breadfruit-fed mice gained more weight overall than wheat-fed mice but the crumbly nature of the diet made accurate food intake measures impossible. Chemical and histological analysis did not reveal any significant difference between the two diet groups suggesting that breadfruit is not toxic. Together, these data demonstrate that breadfruit has potential as a staple protein source for reducing malnutrition in tropical countries and as an ingredient in nutritional products, in particular gluten-free food products, for world markets.
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