Estimation of Starch Hydrolysis in Sweet Potato (Beni Haruka) Based on Storage Period Using Nondestructive Near-Infrared Spectrometry

Abstract

Sweet potatoes are a substantial source of nutrition and can be added to processed foods in the form of paste. The moisture and starch contents of these potatoes affect the physicochemical properties of sweet potato paste. In this study, the changes in the moisture, starch, and α-amylase content of sweet potatoes were measured for eight weeks after harvest. Using nondestructive near-infrared analyses and chemometric models, the moisture and starch contents were predicted. The partial least squares (PLS) method was used for prediction, while linear discriminant analysis (LDA) was used for discrimination. To increase the accuracy of the model, the near-infrared spectrum was preprocessed using the Savitzky–Golay derivative (S–G), standard normal variate (SNV), and multiplicative scattering correction methods. When applying PLS to the moisture content, the best calibration model accuracy was obtained using the S–G preprocessed spectrum. Furthermore, the best calibration model accuracy for starch content was obtained using the SNV preprocessed spectrum. The moisture and starch contents were categorized into five classes for LDA, with results indicating that the internal quality of sweet potatoes can be predicted and classified using chemometric models through nondestructive detection.

The Modelling of Convective Drying Variables’ Effects on the Functional Properties of Sliced Sweet Potatoes

“…Sweet potato (Ipomea batatas) is among the most widely produced food sources in developing countries after grains. These tubers, of which 90 million tons are produced annually in Asian countries and more than 105 million metric tons globally, are used in the production of sweet bread and bakery products [ 1 ]. There are different types, ranging from white to yellow, orange and light purple according to the color of the skin and flesh.…”

Development of NIRS calibration curves for sugars in baked sweetpotato

“…For baked roots the equation was: Sweetness (sucrose equivalent) = 1.2 fructose + 0.64 glucose + 1 sucrose + 0.43 maltose. 18,22 NIRS analyses, calibration development and validation A total of 699 samples were NIRS scanned in this study. Each freeze dried and milled sweetpotato sample was scanned by NIRS within the range of 400-2498 nm, registering the absorbance values log(1/R) at 0.5 nm intervals for each sample using a NIRS monochromator (model FOSS XDS, solid module) and ring cup.…”

“…It is a method of choice among many spectroscopic methods for the assessment of agricultural produce due to its short measurement time, low cost, simple operation, high efficiency, and repeatability. [17][18][19] NIRS methods have been successfully developed for the measurement of the internal quality (moisture and starch content) of raw and dried sweetpotato. 18 It has also been successfully applied to simultaneously estimate starch, protein, sugars, carotenoids, and minerals such as iron and zinc content in raw storage roots of sweetpotato, but there are no published reports of its application for sugars in baked sweetpotato.…”

“…[17][18][19] NIRS methods have been successfully developed for the measurement of the internal quality (moisture and starch content) of raw and dried sweetpotato. 18 It has also been successfully applied to simultaneously estimate starch, protein, sugars, carotenoids, and minerals such as iron and zinc content in raw storage roots of sweetpotato, but there are no published reports of its application for sugars in baked sweetpotato. The current research focused on development and validation of NIRS calibration equations for sugars in a reference set that was subjected to baking, which is a popular method of cooking sweetpotato globally.…”

“…For measuring of nutritional quality without destroying or causing change to the shape or characteristics of macromolecules, non‐destructive methods such as NIRS can be used. It is a method of choice among many spectroscopic methods for the assessment of agricultural produce due to its short measurement time, low cost, simple operation, high efficiency, and repeatability 17–19 . NIRS methods have been successfully developed for the measurement of the internal quality (moisture and starch content) of raw and dried sweetpotato 18 .…”