The new research provides important information to formulators, increasing looking at resistant starch for 'healthier' formulations, particularly in bakery products.
"Although resistant starch producers claim that the sensory properties of bakery products are not modified when resistant starch is used, the results obtained in this study demonstrated that some differences did appear," wrote the researchers from the Instituto de Agroquimica y Tecnologia de Alimentos (CSIC) in Valencia.
"Moisture and sweetness perceptions changed, and grittiness appeared as a new feature.
However, these characteristics did not affect the 'overall acceptability' of these products to consumers," they added.
Starches can be divided into three groups: rapidly digestible starch (RDS, digested within 20 minutes), slowly digestible starch (SDS, digested between 20 and 120 minutes), and resistant starch (RS).
The latter is not digested but is fermented in the large intestine and has 'prebiotic' properties.
Resistant starch can be found naturally in cold cooked potatoes, pasta and rice as well as baked beans and lentils.
Writing in the journal LWT - Food Science and Technology , the researchers explain: "Food applications of resistant starch are of interest to product developers and nutritionists for two reasons, the first being the potential physiological benefits and the second the high final quality of the products, which is not attainable with traditional insoluble fibres.
"The physical properties of resistant starch, particularly its low water-holding capacity, make it a functional ingredient that provides good handling and provides and improves texture in the final product.
"In order for a novel, nutritionally functional ingredient to be accepted by the food industry and consumers, beneficial physiological effects as well as high organoleptic acceptability need to be demonstrated," they added.
The Valencia-based researchers replaced wheat flour with a commercial resistant starch (Hi-Maize 260, National Starch Food Innovation) at 0, 5, 10, 15 and 20 per cent in baked muffins.
The muffins were analysed by 50 people who were regular consumers of muffins.
About half of the panelists were women.
No significant difference was reported in 'taste', 'overall acceptance' and 'consumption intention', report the researchers.
However, the 'appearance' and 'texture' attributes were significantly different.
To further understand the differences, the researchers used a panel of ten trained tasters, who reported decreases in scores of 'cohesiveness', 'typical taste', 'typical odour', 'number of gas cells', 'springiness', and 'chewiness'.
On the other hand, the perception of moisture increased after formulation with resistant starch.
"It is interesting to emphasize that in addition to the traditional attributes in bakery products as 'sweetness', 'taste', 'odour', 'chewiness', or 'springiness', other new attributes appeared from the preliminary sensory sessions that were distinctive for RS-added muffins," wrote the researchers.
"These were 'number of gas cells', 'grittiness', and 'moisture' perception and were included in the sensory evaluation of the muffins."
Foods with a low GI value keep the body's blood sugar levels relatively steady throughout the day, regulating appetite and reducing the tendency to snack.
Although there is no evidence to show that a low-glycaemic index diet is any more effective than a low-fat, high GI diet for weight loss, low GI foods are increasingly being positioned as weight management foods, partly because they may also have benefits in preventing obesity-related disease like type 2 diabetes.
Source: LWT - Food Science and Technology (Elsevier) Published online ahead of print 1 February 2008, doi: 10.1016/j.lwt.2008.01.012 "Distinctive sensory features introduced by resistant starch in baked products" Authors: R. Baixauli, A. Salvador, S. Martinez-Cervera, S.M. Fiszman