The Implications of Sample Preparation on the Quantification of Resistant Starch Type 1 and Related Nutritional Starch Fractions in Plantain (Musa AAB)
Sample preparation is a critical step in any analysis and could influence the reliability of results. Analysing some dietary carbohydrates using flours and milled samples could affect the results obtained. The resistant starch type 1 (RS1) content from many foods has not been reported. This may be due to the fact that many investigations on the quantification of resistant starches have been centred on measuring resistant starch in starches/flours, and the consequences are that intact food matrices that would have aided the identification of RS1 in the foods would have been disrupted by milling.
In this study, enzyme hydrolysis was used to quantify RS1 in raw and boiled plantain, and two sample pre-treatments were compared. The two types of samples used were (i) samples prepared in the ‘as eaten’ manner, which reflect in vivo conditions in exactly the way the food is consumed and (ii) samples prepared in the conventional dry powder method.
RS1 was quantified in the samples analysed on ‘as eaten’ basis, while RS1 was not detected in the dried and powdered samples. Raw unripe plantain had the highest quantity of RS1 (7.3 ± 2.9 g/100 g) while no RS1 was detected in boiled ripe plantain. Dry powder analyses of boiled unripe plantain samples indicated a loss of RS1, slowly digestible starch (SDS) and a corresponding increase in rapidly digestible starch (RDS). The implication of this is that available carbohydrates will be overestimated using this method, which may further affect glycaemic index (GI) measurements.
KeywordsRS1 Sample preparation Rapidly digestible Resistant starch Plantain Glycaemic index
The author gratefully acknowledges the Commonwealth Scholarship Commission, United Kingdom, for funding this research work and the School of Food Science and Nutrition, University of Leeds for providing support.
Compliance with Ethical Standards
This study was funded by the Commonwealth Scholarship Commission, United Kingdom (grant number NGCA-2009-51).
Conflict of Interest
Ebun-Oluwa Oladele declares that she has no conflict of interest.
This article does not contain any studies with human participants or animals.
Informed consent was not applicable.
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