Attributes and characteristics of fibre products

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CHAPTER 2 LITERATURE REVIEW

Introduction

Prior to 1965, fibre was referred to as roughage or bulk and was measured as crude fibre. It is only in the past twenty-five to thirsty years that fibre, now called Dietary fibre, has been given the scientific importance (Chawla & Patil, 2010). Fibre was first described as the skeletal remains of plant cell walls that are resistant to hydrolysis by the digestive enzymes of man (Phillips & Williams, 2000). These include cellulose, hemicelluloses, pectin, and lignin that are present in a variety of foods such as cereals and legumes among others (IUFoST, 2009). Nowadays, however, the definition is broader, including not only non-edible parts of vegetables but also fibres from animal origin whose molecular structure is similar to that of plant cellulose (Borderias et al., 2005). Dietary fibre are said to be resistant to the enzymes of the human and animal gastrointestinal tract. Through their physical properties, soluble and non-soluble fibres exert their action by increasing digested mass and holding water in the stomach and small intestine, leading to relief of constipation (Phillips & Williams, 2000). The American Dietetic Association supports the position that consumers should have adequate amounts of dietary fibre from a variety of plant foods. The recommended intakes of 20-35g/day for healthy adults and 5g/day for children are not being met because intakes of good sources of dietary fibre, fruits, vegetables, whole and high-fibre grain products, and legumes are low (Marlett et al; 2002). The European Food Safety Authority panel on dietetic products, nutrition and allergies was asked to give an opinion on dietary fibre intake. The role of bowel function was used as suitable criterion for establishing an adequate fibre intake. Based on the evidence on bowel function, the panel considered dietary fibre intake of 25g per day to be adequate for normal laxation in adults confirming the American Dietetic Association statement. There was, however, limited evidence to set adequate intakes for children. The panel suggested that adequate intake for dietary fibre for children should be based on that of adults with adjustment for energy intake (EFSA, 2010). In her study on characterisation of dietary fibre properties to optimise the effects of human metabolism, Ulmius (2011) found that, on average, women showed a more pronounced glucose lowering response than men when rye bran was used. This was considered an indication that different amounts of dietary fibre should be recommended for men and women. The definition of dietary fibre and methods of analysing have been subjects of intense debate and research. A demand of a global definition has risen and the legislation on food labelling, nutrition and health claims is also asking for a uniform definition of dietary fibre (Raninen et al., 2011)

Overview on previous studies

During the thirty second session of the Codex Alimentarius Commission in Rome, dietary fibre was re-defined and described as one of three categories of carbohydrate polymers; carbohydrate polymers obtained from food raw material by physical, enzymatic or chemical means; and systematic carbohydrate polymers (FAO/HWO, 2009). Dietary fibre is increasingly being linked to health benefits. The beneficial properties of dietary fibre have been associated with their significant role in human physiological function such as reduction in cholesterol level and blood pressure, prevention of gastro-intestinal problems, and protection against several cancers have been reported (Chawla & Patil, 2010). Dietary fibre is also documented to lower risk of heart disease and diabetes (Mehta, 2009). This has been explained by the viscous effects of soluble fibre which can reduce or delay the absorption of carbohydrates and fat in the small intestine, resulting in lower blood concentrations of glucose, insulin and cholesterol (Ulmius, 2011). A fibre-rich meal is processed more slowly, promoting earlier satiety and is frequently less caloric in fat and sugars. These characteristics are attributes of a dietary pattern to treat and prevent obesity (Marlett et al., 2002). In a study done in Australia on bread, researchers found that bread enriched with lupin kernel flour reduced blood pressure and boosted heart health (Lee et al., 2009). Researchers from the National Institute of Environmental Medicine in Sweden in collaboration with the National Public Health Institute in Finland and the National Cancer Institute in USA determined the relationship between dietary fibre and risk of stroke in male smokers. Findings suggested a beneficial effect of the consumption of fruits, vegetables and cereals on stroke risks (Larsson et al., 2009) People who eat whole grains tend to have less of the type of fat associated with heart health and diabetes risk than those who eat more refined grains (McKeown, et al., 2009). To examine the association between dietary fibre intake and colorectal cancer risk Dahm et al., conducted a study in the United Kingdom in 2010. The results showed that intakes of absolute fibre were statistically significantly inversely associated with the risks of colorectal and colon cancer. Researchers from the University of Mediterranee in France have examined the relationship between the source or type of dietary fibre intake and cardiovascular disease risk factors in adults men and women. Their findings suggested that the highest total dietary fibre and non-soluble dietary fibre intakes were associated with a significantly lower risk of overweight and elevated blood pressure in both sexes (Lairon et al., 2005).The American Diabetes Association released an article on a study done on the association between dietary fibre and inflammation, hepatic function in older men. Findings of the study also confirmed that dietary fibre is associated with reduced diabetes risk (Wannamethee et al., 2009). According to Bijkerk et al., 2009, adding soluble fibre to the diet improves symptoms associated with irritable bowel syndrome (IBS). In a study led at the University of Minnesota in the United States of America, researchers found that beta-glucan significantly reduced total and LDL cholesterol in subjects with elevated cholesterol levels. Based on a model intestinal fermentation, this fibre was fermentable. Thus it can lower serum lipids in a high risk population and may improve colon health (Queenan et al., 2007). In a recent study conducted by the National Cancer Institute in Maryland in the United State of America, it has been found that fibre intake lowered the risk of death from cardiovascular infections, and respiratory diseases by 24 percent to 56 percent in men and by 34 percent to 59 percent in women (Park et al., 2011). A study led in Japan showed that higher intake of both soluble and insoluble dietary fibre, especially from fruit and cereal sources, may contribute to the prevention of coronary heart disease in Japanese men and women (Ehab et al., 2010). Eating a high-fibre breakfast from rye has been found to increase feelings of satiety and leads to reduced food intake later in the day. This decreases chances of obesity (Isaksson et al., 2009). Preliminary findings on fibre-enriched pasta form the Laboratory of experimental Biochemistry in Bari, Italy, suggested that consumption of fibre-enriched pasta produced significant increases in levels of gut peptides linked to the emptying of the stomach and ease the rise in blood sugar levels after eating compared to consumption of the control pasta (Russo et al., 2011). Danone research findings led in America suggested that formula enriched with fibre may protect healthy infants from allergy. The study results showed significant reduction in the incidence of atopic dermatitis in low-risk children (Gruber et al., 2010). The department of epidemiology at the University of Washington have conducted a study on dietary fibre intake in early pregnancy and risks of preeclampsia. Results suggested that higher total fibre intake may attenuate pregnancy-associated preeclampsia (Qiu et al., 2008). In China, research done on four hundred and thirty-eight cases with primary breast cancer suggested that consumption of total dietary fibre and fibre from vegetable and fruit sources was inversely associated with breast cancer risk (Zhang et al., 2011).
Dietary fibre is also beneficial to food manufacturers. Dietary fibre are used in the food industry to fortify foods products, increase their dietary content resulting in healthy products, low in calorie, cholesterol and fat. They also play a functional role by improving food products texture, physical and structural properties of hydration, oil holding capacity, viscosity, sensory characteristics, and shelf-life (Elleuch et al., 2010). Food and beverage companies have recognised the role that an increase in dietary fibre could play in the promotion of new products. In their study, Bogue & Troy’s objectives were to understand consumers’ attitudes towards fibre products, to assess the role of fibre in the diet gain an insight into the impact of health claims on willingness to purchase healthy food and to explore consumers’ view on a beta-glucan enriched food product or beverage. Findings of the study suggested that consumers generally had a positive attitude towards fibre-enriched food products. They claimed fibre-enriched products healthy and familiar. However, consumers showed a high level of mistrust towards health claims although health claims attracted them to the specific product (Bogue & Troy, 2008). Dietary fibre can be added in bakery products to improve texture. The fibre will influence water absorption during formation of the dough and batter (Mahta, 2009). In a study on ice-cream, Soukoulis et al., 2008, found that dietary fibres controlled crystallization and re-crystallisation in ice creams and therefore offered new formulation possibilities to product developers.
Substituting partially hydrogenated vegetable fat, used as flavour fixative agent in snacks, with fibre increases the dietary fibre content of the finished product sevenfold with similar overall acceptability and these results in production of a healthy snack (Capriles et al., 2009). It has been found that yoghurt enriched with edible fibre obtained from the non-edible part of asparagus increased the consistency of the yoghurt (Sanz et al., 2008). Dietary fibre guar gum was successfully incorporated in low fat yak milk with improved body, texture and juiciness (Kandeepan & Sangma, 2010). Muffins containing an orange-based dietary fibre were developed to determine chemical composition, starch digestibility, Glycaemia Index and sensory characteristics. Results showed low fat and high fibre contents, a decrease in Glyceamic Index but no difference in other attributes when compared with the control muffin. These findings proved that the addition of fibre can be an alternative for people who require low glyceamic response (Romero-Lopez et al., 2011). Researchers from the faculty of Land, food and leisure at the University of Plymout in the United Kingdom studied the nutritional and physicochemical characteristics of dietary fibre enriched pasta. Results showed that the added fibre influenced the cooking and textural characteristics of both raw and cooked pasta. Glucose release was said to be significantly reduced by the addition of soluble dietary fibre (Tudorica et al., 2001). Development of dietary fibre-enriched foods results in obtaining products with good functional properties but can cause problems in technological properties. With this in mind, the effect of dietary fibre on technological quality of pasta was studied by replacing a portion of wheat flour with four types of dietary fibres. The one type improved the overall quality of the final product, the second fibre only improved the product texture, the third improved cooking characteristics and the fourth negatively affected the end product characteristics. These results proved that pasta can be developed with good cooking quality and improved nutritional characteristics by adding a combination of appropriate dietary fibres (Bustos et al., (2011). The effect of grape antioxidant dietary fibre on the prevention of lipid oxidation in minced fish was evaluated by researchers in Spain. The study findings suggested that addition of red grape fibre delayed lipid oxidation in minced horse mackerel muscle during the first three months of frozen storage (Sanchez-Alfonso et al., 2005). As dietary fibre describes a wide variety range of non-digestible carbohydrate with different biochemical and biophysical properties, different sources and type of dietary fibre have different functionality in food products as well as different consequences to human physiology (Brownlee, 2009). In this study, consumers’ attitudes, perceptions and willingness to purchase high fibre products were defined using dichotomous choice questions. This method has been used by a number of researchers. Lupin et al., (2008) has done a survey on consumers’ willingness to purchase organic food in Argentina. The results were that, informed consumers were willing to pay price premiums for organic products. Lack of store availability reliable regulatory system to control quality risks rather than price seemed to be the reason of the constraint consumption of organic products in Argentina. Prior to this study, Lupin and other researchers evaluated consumers’ perceptions of food quality attributes and their incidence available organic foods. Results showed that 67% were worried about their health, 79% take care in meals, 57% perceived the high risk of hormones and pesticides in food, and 91% are used to read labels before purchasing (Lupin et al., 2006). Gil et al., (2000) and Molla-Bauza et al., (2005) conducted a similar study in Spain and found that some consumers were willing to pay a premium for organic food depending on their lifestyles and attitudes towards environment issues. Both Lupin and Molla-Bauza conclusions stated a positive consumer willingness to pay a premium, but producer’s challenge remained in the high prices of organic products compared to conventional products. Molla-Bauza’s concluding results on wine emphasised that consumers who were willing to pay these premiums were mostly concerned about environmental issues and less about health. However, most of those respondents who were willing to pay high prices came from the healthy life style group. The University of Alberta in Canada conducted a research on willingness to pay for organic wheat bread. Findings of the study showed that in the absence of taste information, willingness to pay was greater when environmental information was given than willingness to pay when health information was given. Once sensory information was given, willingness to pay with health information was twice that of the environment. Health claims seemed to be taken into consideration only when the product was tasted (Boxall et al., 2009). Recently in Turkey, consumers’ willingness to pay extra money for organically raised chicken meat rather than conventionally raised chicken meat was evaluated. Findings of the study revealed that 81% of the respondents would be willing to pay a premium for organically raised chicken meat. Results also showed that willingness to pay was related to household income, education level of household head and monthly chicken meat consumption (Gunduz and Bayramoglu, 2011). Munene (2006) from the Department of Agricultural Economics and Agribusiness at the University of Louisiana analysed consumer attitudes and their willingness to pay for functional foods. Beliefs about the link between nutrition and health, concern about chronic diseases, current purchasing and consumption patterns, and attitude towards functional foods were factors that were found to have significantly affected the respondents’ willingness to pay a premium for functional foods. Prathiraja and Ariyawardana (2003) of the University of Peradeniya in Sri Lanka have found that consumers use nutritional labelling when making a purchasing decision because of their health consciousness. Findings of their study on the impact of nutritional labelling on consumer buying behaviour showed that the majority of respondents were willing to pay more money for the nutritional information on food items. Results of a study on white bread enriched with fibre, suggested that consumers were ready to pay more for bread labelled source of fibre on a single purchase. The study, however, underlined the importance of sensory characteristics such as taste and appearance but questioned whether the same consumers will be willing to pay more for regular, repeated purchases (Ginon et al., 2009). In a similar type of study in Switzerland, consumer willingness to pay for breakfast cereals, hard bread and potato products, study results suggested that consumers who preferred nutrition over taste for some ingredient in a specific product may prefer taste over nutrition for other products (Rausser & Thunstrom, 2009). In 2005, Lyly et al., researchers from the technical research centre of Finland , France and Sweden worked on factors that influence consumers’ willingness to use beverages and ready-to-eat frozen soups containing oat beta glucan in 2005. The results showed that after tasting, the price consumers were willing to pay for beverages and soups decreased. Taste of the products strongly affected the willingness to pay. Health claim gave a significant but small added value. Ares et al (2008) also studied the effect on sensory properties and consumers’ acceptability. The effect of the addition of a functional fibre on sensory characteristics and consumers’ acceptability of milk puddings was determined. Using different concentrations (between 0 and 4%), researchers discovered that higher concentrations caused changes in the sensory characteristics of milk puddings. Concentration of 1.4% was estimated as the maximum as the maximum concentration that does not significantly modify consumers’ overall acceptability. Consumers who would buy milk desserts containing 1.4% fibre was estimated as 71%. Concentrations above 1.4% were said to cause a rough after feel and floury taste. In a study on pesticide free food products at the University of Guelph in Canada, Magnusson and Cranfield (2003) used Contingent Valuation survey to determine if Canadian consumers were willing to pay more for pesticide free food products. Sixty five percent of respondents were willing to pay a 1 to 10% premium relative to conventional food product. Five percent were willing to pay more than a 20% premium. Boccaletti and Moro conducted a survey in Italy to measure consumer willingness to pay for genetically modified food products. Their findings suggested that 46% of the respondents had a positive attitude towards GM foods and only 27.5% rated a negative attitude. All respondents based their responses on health and environmental issues. 39.5% showed an neutral response towards GM and traditional food products if quality and prices were held the same, and another 22 % said they would consume GM foods even if the price was slightly higher (5%). Willingness to pay was mainly affected by income and information (Boccaletti & Moro, 2000)

TABLE OF CONTENTS
List of tables
List of figures
Acknowledgement
Declaration
Abstract
CHAPTER 1 INTRODUCTION
1.1. Background
1.2 Study area
1.3 Problem statement
1.4 Research objectives
1.5 Data collection and methodology
1.6 Study limitations
1.7 Chapter outline
CHAPTER 2 LITERATURE REVIEW
2.1 Introduction.
2.2 Attributes and characteristics of fibre products
2.3 Overview on previous studies
2.4 Conclusion
CHAPTER 3 RESULTS AND DISCUSSION
3.1 Survey response rate
3.2 Descriptive statistics of variables used in the analysis
3.3 Results of the regression analysis
3.4 Conclusion
CHAPTER 4 CONCLUSIONS AND RECOMMENDATIONS
4.1 Main findings
4.2. Recommendations
REFERENCES
GET THE COMPLETE PROJECT
MARKET SEGMENTATION AND CONSUMER WILLINGNESS TO PAY FOR HIGH FIBRE PRODUCTS: THE CASE OF JOHANNESBURG AND THE SURROUNDING AREAS, SOUTH AFRICA.