Breadfruit (Artocarpus altilis): The impact of environment on nutritional composition and implications for Hawaiʻi communities

Abstract

Breadfruit (Artocarpus altilis) is an evergreen tree of the Moraceae family that produces large starchy fruits. It is a highly productive and long-lived tree crop that has the potential to contribute greatly to human and environmental health and well-being. The crop is known to aid in soil retention and soil carbon sequestration as an agroforestry component, and is rich in carbohydrates (starch, resistant starch and fiber), specific amino acids and some vitamins and minerals. As breadfruit gains interest among local communities around the world for its many nutritional and environmental benefits, it has become important to understand several components of the fruit and its growing environments. This project aimed to examine the effect of climate and soil variables on nutritional qualities of breadfruit. Three related studies were conducted: a meta-analysis of previous data sets, laboratory analyses of fruit nutrition, and a consumer survey. In the first, globally-comprised nutritional studies in breadfruit were collected and location of each study was used to extract climate and soil data using GIS software. Nutritional qualities of raw, mature breadfruit were analyzed by study site in order to examine the effects of varying abiotic factors – namely climate and soil. Findings indicate that climate and soils affect categories of breadfruit nutrition in different ways. Precipitation and cation exchange capacity of soil are significant influencers to nutritive aspects of breadfruit, especially the level of vitamins and to a lesser degree of proximate nutrients (protein, fat, fiber, energy, ash and moisture); in general, macro- and micro-nutrients were unaffected by climate and soil variables. Following the global review, a Hawaii-based study was conducted with the objective of using Hawaii’s diverse microclimates to further explore the effects of the abiotic environment on breadfruit nutrition; it was hypothesized that these small yet significant differences from place to place may have noteworthy effects on breadfruit nutritional value. Sample fruit from 48 different farms across four of the Hawaiian Islands were collected and analyzed first for nutrient composition. A parallel study derived soil and climate data for each site, from which I utilized data. Cultivar type played a large role in nutritional values. Overall results showed similar trends as those found among the globally-represented data. Proximate nutrients were affected by climate, however in this case soil characteristics played a more significant role. Furthermore, multivariate analysis showed that climatic variables and soil characteristics combined displayed the most significance in terms of influencing nutritional variation. Macro- and micro-nutrients, again, were overall unaffected by either set of environmental variables. Lastly, a consumer survey was created and administered to Hawai’i residents in order to gain insight into how local people are interacting with the fruit. Questions were crafted around consumption patterns, preparation methods, and health benefit awareness. Findings showed that on average people will eat about 13 servings of breadfruit per year, but with a large standard deviation and a distribution that demonstrates exponential decay. Essentially, vast majority of people eat breadfruit three times per year or less, but a few people eat a lot of it which results in an average value that is a bit deceiving. The survey also indicated that a person will eat about one quarter of a whole fruit in one sitting (per meal). Fruit are prepared mostly by steaming, baking, and frying. About 43% of respondents were aware of some type of health benefit associated with consuming the fruit. One of the most determining factors to overall consumption was having a backyard tree; people with their own tree ate about twice as much breadfruit as those who do not. Nearly 71% of respondents rely on a backyard tree for obtaining fruit – either their own or a family member’s or friend’s tree. Conversely, only 5% of consumers ever obtain fruit from a market. In addition, open-ended comment boxes were often used by participants to interject the difficulty in finding fruit (sources). This provides some insight into how breadfruit consumption can be improved as well as brings to attention the issue of accessibility to breadfruit sources.