Renata Barczynska

New starch preparations resistant to enzymatic digestion

BACKGROUND New starch preparations were produced by thermolysis of potato starch in the presence of inorganic (hydrochloric) and organic (citric and tartaric) acids under controlled conditions. The starch preparations were physicochemically and structurally characterised and analysed for their resistance to enzymatic digestion in vitro. RESULTS The content of resistant fraction in dextrin D1, obtained by heating starch acidified with hydrochloric and citric acids, determined by the AOAC 2001.03 and pancreatin-gravimetric methods was similar (~200 g kg⁻¹). In the case of dextrin D3, obtained by heating starch acidified with hydrochloric and tartaric acids, the result of determination by the pancreatin-gravimetric method was almost four times higher than that obtained with the AOAC 2001.03 method. The enzymatic tests revealed that dextrin D3 obtained with excess tartaric acid can be classified as RS4, which can only be partially determined by enzymatic-gravimetric methods. Tartaric acid at high concentration had a significantly stronger influence on starch hydrolysis than citric acid. This was confirmed by chromatographic analysis of dextrins and chemical investigation of the reducing power. CONCLUSION The results confirmed the possibility of applying dextrins, prepared under specific conditions, as soluble dietary fibre.

Dextrins from Maize Starch as Substances Activating the Growth of Bacteroidetes and Actinobacteria Simultaneously Inhibiting the Growth of Firmicutes, Responsible for the Occurrence of Obesity

Unarguably, diet has a significant impact on human intestinal microbiota. The role of prebiotics as substances supporting the maintenance of appropriate body weight and reducing the demand for energy via stimulation of the growth of beneficial microbiota of the gut and formation products such as short-chain fatty acids, is more and more often highlighted. The objective of this study was to evaluate whether dextrins from maize starch resistant to enzymatic digestion stimulate the growth of Bacteroidetes and Actinobacteria strains representing a majority of the population of colon microbiota in lean individuals and limit the growth of Firmicutes bacterial strains representing a majority of the population of colon microbiota in obese individuals. The study was conducted with the use of in vitro method, using isolates from faeces of children characterized by normal weight, overweight and obesity. It was demonstrated that dextrins from maize starch equally efficient stimulate the growth of the isolates derived from normal-weight, overweight and obese children, and therefore may be added to foods as a beneficial component stimulating growth of strains belonging to Actinobacteria and Bacteroidetes for both overweight, obese and normal-weight children.

Resistant Dextrins as Prebiotic

In current days, the way each of human beings live indicates his or her health in the future time. Many factors determine the risk of illnesses, or reversibly, the possibility of being healthy. Being physically active and consumption of appropriate diet are examples of daily routines that may influence the condition of an organism. Lack of physical activity, particularly if associated with over consumption, increases the risk of development of nutrition related chronic diseases, such as obesity, hypertension, cardiovascular diseases, osteoporosis, type II diabetes, and several cancers. Over the last decade, drastic changes have taken place in the image and assessment of the importance of the daily diet. Foods are no longer judged in terms of taste and immediate nutritional needs, but also in terms of their ability to improve the health and well-being of consumers. The role of diet in human health has led to the recent development of the so-called functional food concept. A functional food is dietary ingredient, that has cellular or physiological effects above the normal nutritional value. Functional food can contain probiotics and/or prebiotics.

Effects of dietary fiber preparations made from maize starch on the growth and activity of selected bacteria from the Firmicutes, Bacteroidetes, and Actinobacteria phyla in fecal samples from obese children.

Currently, there is a search for substances that would be very well tolerated by an organism and which could contribute to the activation of the growth of Bacteroidetes and Actinobacteria strains, with simultaneous inhibition of the growth of Firmicutes. High expectations in this regard are raised with the use of fiber preparations from starch - resistant corn dextrins, branched dextrins, resistant maltodextrins and soluble corn fiber. In this paper, the influence of fiber preparations made from corn starch was evaluated on growth and activity of Bacteroidetes, Actinobacteria and Firmicutes strains isolated from obese children. It was demonstrated that in the stool of obese children Firmicutes strains predominate, while Bacteroidetes and Actinobacteria strains were in the minority. A supplementation of fecal culture with fiber preparations did not cause any significant changes in the number of strains of Bacteroidetes and Firmicutes. Addition of fiber preparations to the fecal samples of obese children increased the amount of short-chain fatty acids, especially acetic (p < 0.01), propionic, butyric (p = 0.05) and lactic acid (p < 0.01).

Dietary resistant dextrins positively modulate fecal and cecal microbiota composition in young rats.

The objective of the present study was to demonstrate the effect of dietary resistant dextrins, as potential prebiotics, on the intestinal microflora of young rats. Enzyme-resistant dextrin, prepared by heating of potato starch in the presence of hydrochloric (0.1% dsb) and tartaric (40% dsb) acid at 130ºC for 2 h (CA-dextrin). The experiment was performed on 24 Wistar male rats at 3-wk of age, divided by analogues in three experimental groups (control, starch and dextrin). Analyses determined the overall bacterial counts and the counts of Lactobacillus, Bifidobacterium, Bacteroides and Clostridium strains within the feces and cecal contents of rats using fluorescence in situ hybridization method. CA-dextrin had no effect on primary growth indicators (body weight, body weight gain, dietary consumption) or the mass of the small intestine and the cecum, but dextrins caused a reduction in pH and the concentration of ammonia within the cecal contents. That supplementation of diet with resistant dextrins had a positive effect on composition of intestinal microflora in rats. It increased the counts of Bifidobacterium and Lactobacillus strains both in the feces and in the cecum. Moreover, it reduced the counts of Clostridium and Bacteroides strains. These results may suggest that resistant dextrins exerted a prebiotic-like effect in the large intestine.