Assessing Gastrointestinal Tolerance and Palatability of Fibre-enriched Bread: a Randomised Control Trial.

Abstract

Objective: The aim was to produce a fibre-enriched bread that contained 10g of fibre per serve (two slices), an amount approximately equivalent to the deficit in fibre intake between the average intake of adult New Zealanders and the nutrient reference value. This was incorporated in a convenient and widely consumed food vehicle (bread) and tested for palatability and gastrointestinal tolerance. Design: Randomised double-blind crossover control trial. Method: A total of 79 healthy University of Otago students enrolled in the undergraduate Human Nutrition course participated in the study. They were randomised to either a Fruit fibre enriched bread (and control) or a FibreMaxTM enriched bread (and control). Participants consumed approximately ten grams of the test fibre in two slices of bread. The palatability rating of the bread was assessed using a questionnaire composed of six visual analogue scales; visual appeal, smell, taste, texture, aftertaste and overall pleasantness. Gastrointestinal symptoms experienced including bloating, abdominal rumbling, flatulence, abdominal pain, nausea and vomiting were then rated using gastrointestinal questionnaires at baseline and one, two, three, eight and 24 hours post bread consumption. Results: Both the FibreMaxTM and Fruit fibre-enriched breads were well tolerated. More people reported feeling nauseous after eating the Fruit fibre bread compared with it’s control (p=0.02). There were no other differences between the Fruit fibre bread and it’s control, or between the FibreMaxTM bread and it’s control. The FibreMaxTM bread was visually less appealing than it’s control (P=0.0039), although the overall palatability scores were not statistically different between the bread types (P=0.87). The Fruit fibre bread was less acceptable and had a lower median score for taste (P=0.0005), smell (P=0.0003), rating of aftertaste (P=0.0000) and overall palatability rating (P=0.0003) compared with it’s control. Conclusion: Both fibre-enriched breads were digestively tolerated in a single serve. Apart from the Fruit fibre having a poor taste and aftertaste that will require reformulation, the two fibre products created moist and palatable bread. There is place in the market and considerable potential for affordable and palatable bread with 10g fibre in a single serve (two slices), which does not induce gastrointestinal discomfort, such as those used in this study. If developed commercially it has the potential to reduce the gap between a low-fibre consumer’s actual and recommended fibre intake.