Composite Bread Fruit-Sweet Potato Flour Substitution In Bread Production

Introduction

Breadfruit and sweet potato are Traditional staples consumed in the Caribbean region. These traditional staples are particularly appealing to the region not only because of their nutritional and caloric value and contribution to livelihood systems, but also because of their adaptability to a wide range of growing conditions and their low sensitivity to natural disasters, such as hurricanes, which often plague the region. Wheat flour has surpassed these traditional foods like cassava, bread fruit and sweet potato. CARICOM countries are encouraged to consume more local food plants and decrease their reliance on imports of food. Two potential plants are breadfruit (Artocapus altilis. L of the family Moraceae) and sweet potato (Convolvulaceae family Ipomoea batatas).

Researchers agree that sweet potato is an inexpensive carbohydrate and an excellent source of vitamins and micronutrients like manganese. This crop, however, is underused and has the ability to be used in the human food system. (Van Hal 2000) (Walter,W. M Truong, V.D and Espinel K.R 2002) Several constraints affect the sustainable development of the region's sweet potato industries, including low yields attributed by producers to generally poor farming methods, poor quality due to pests and diseases (arthropods and pathogens) in both pre-and post-harvest stages.

Poor intelligence on the market and limited knowledge of the market have also impeded development. Furthermore, although sweet potato is a staple food in many developing nations, moisture loss, rotting, sprouting or modifications in sensory products such as flour limit its shelf life. It was also reported that bread fruit is rich in fat, ash, fiber and protein (Ragone 1997).

Despite this fruit's nutritional value and importance, its production faces several challenges including short shelf life. One way to minimize post-harvest losses and increase breadfruit use is through flour processing. In many developing countries, promoting the use of composite flours has the following advantages: improved overall use of domestic agricultural production, currency savings, promotion of high yield, native species, improved protein, human nutrition and food security. These crops have the ability to sustainably address food insecurity and food import bill problems in CARICOM.

The overall goal of food and nutrition security policy is to improve the health and well-being of all Guyanese by improving food and nutrition security. This will be accomplished by enabling sustainable and stable jobs possibilities that would boost food availability and accessibility, particularly among vulnerable groups. Encouraging mechanisms for the use and consumption of healthy foods to enhance intuitive coordination and functioning to improve food and nutrition security. (Food and Nutrition Security Strategy, MOA 2011). Food security was described at the 1996 World Food Summit in Rome as 'when all individuals have access to adequate, safe, nutritious food at all times to preserve a good and active life' (World Bank 2007).

This study will assess the proximate composition, physical properties and sensory characteristics of bread produced from composite bread fruit-sweet potato flour substitution with wheat flour. Bread is a traditional and cultural food in the daily diet of Guyanese, is often made from wheat. However, it can be made from other cereals such as maize, barley, rice, sweet potato, breadfruit, cassava and other non-grain crops. Wheat bread was reported having increased consumption since 1995, Kihlberg, et al, (2004). Bread made from non-wheat flours in combination with wheat flour are becoming more popular among customers because of the nutritional value, flavour and colour. Brown, (1996).

Literature Review

Sweet Potato

The seventh largest food crop in the world is sweet potato (Ipomoea Batatas Lam). Cultivated in many tropical and subtropical areas. Sweet potato is a very important traditional crop in the developing countries. It generates over 135 hundred metric tonnes of edible food in the world annually (Horton D, Fano H 1985)

In India, this crop in 2005 covered 100,000 ha, with 900,000 MT of manufacturing (FAO, 2006). Due to its brief maturity period and capacity to grow under varied climatic conditions and on less fertile soil, sweet potato has a great potential to be used as a food in developing countries with restricted resources. There are countless options for sweet potato goods, and based on latest diagnostic assessments in developing nations; among the most promising were dried chips, starch, and flour ( (A 1989)Sweet potato flour can serve as a source of energy and nutrients (carbohydrates, beta-carotene (provitamin A), minerals (Ca, P, Fe, and K)) and can add natural sweetness, colour, flavor and dietary fiber to processed products (Woolfe, 1992; Ulm, 1988).

Some Major Components of Sweet Potato

Carbohydrate

Sweet potato can contain dry matter as much as 44% (Moorthy, 2002; Hoover, 2000). Most commercial cultivars, however, contain 20-30 percent dry matter, particularly in the US. The main elements of dry matter are carbohydrates, which in most cultivars make up 90% of dry matter. The main carbohydrate elements are starch, which is 60-70% amylopectin and 30-40% amylose (Huo et al., Chenn et al., 2002; Moorthy, 2002; Hoover, 2001;). The raw uncooked roots contain a significant amount of Sucrose, but there is also glucose, fructose and maltose in cooked roots. (Valetudie et al., 1999; Thorne et al., 1983). The rest of carbohydrates (mainly cellulose, hemicellulose and pectin) are collectively referred to as fiber.

Fiber Content of Sweet Potato

Sweet potato fiber content varies based on the plant type and age. Bradbury et al. (1988 and 1989) reported the fiber content improves with maturity. Different proportion in fiber and ash content in separate root tubers was also reported. Fiber content in derived flours may differ to a higher extent from the methods and sieves used for removal of the fibrous material. Sweet potato flour (2-3% fiber) had distinct compositions than isolated starch (0.1-0.15% fiber) (Moorthy, 2002).

Breadfruit (Artocarpus altilis) is a flowering tree species in the Moraceae family of mulberries. Originally from tropical areas like the South Pacific, Malaysia and the Caribbean. It's a very helpful plant, but it's usually underutilized. The trees generate valuable fruit with some fruiting throughout the year, mainly between May and August.

The evergreen trees grow to 15-21 m (48-70 ft) or higher heights and the trunks at the base can be as large as 2 m (6.6 ft) in diameter. The fruit is round or ovoid, weighing between 2 and 10 pounds in diameter 3-8. In 3-5 years, the trees start to bear and have been productive for many centuries. Due to the elevated carbohydrate level discovered in the body, breadfruit is most often consumed as a staple food. It is also a wealthy mineral, fiber and vitamin source. Due to variation in maturity, environmental variables and cultivars, the dietary content may differ. Breadfruit is a precious food resource that is used primarily in rural societies.

However, present use of mature fruits is restricted and must be utilised within 4-5 days of harvesting. The short shelf life and bad storage characteristics provide for flour conversion, this will increase the storage and versatility of flour. It has been described as an important staple food of high economic value and there is an excellent market potential to use the crop to develop value-added products.

First and foremost, the fermentation process is important for obtaining a gaseous dough and voluminous bread. This happens when the yeast and bacteria – either naturally present in the flour or added – by enzymatic activity splits glucose (released from the starch complexes in the flour) into CO2, water and ethanol. While the water and ethanol are evaporating, the CO2 makes the gluten network stretch (Ledsaak & Eben, 2010; Mondal & Datta, 2008). Moreover, it is well-known that the fermentation affects the flavour of the bread. Both the amount of yeast and the fermentation time are crucial factors in this context (Meyer, 2009). Finally, the fermentation is considered to affect the bread’s nutritional value.

For example, it is observed that some fermentation methods increase the levels of different health-promoting substances (e.g. vitamins) and lower the concentration of anti-nutritional components like phytate (Meyer, 2009). The practice of yeast-leavening has been known since the ancient Egyptians discovered that yeasts (Saccharomyces cerevisiae) used in the brewing of beer also exerted beneficial effects when added in bread doughs.