Effect of Pretreatments and Drying Methods on Physical and Microstructural Properties of Potato Flour

Abstract

This study evaluated the effects of pretreatments (blanching (60 and 95 °C) and boiling) and drying methods (freeze-drying and oven drying) on the quality characteristics of potato flour derived from three potato varieties, namely, Shangi, Unica, and Dutch Robjin. The percentage flour yield, color, particle size distribution, flow characteristics, microstructural and functional properties of the potato flour were determined. Unica recorded the least peeling loss, while the Dutch Robjin variety had the highest. Color parameters were significantly affected (p < 0.05) by the pretreatments and drying methods. Freeze drying produced lighter potato flour (L* = 92.86) compared to the other methods. Boiling and blanching at 95 °C followed by oven drying recorded a low angle of repose and compressibility index, indicating better flow characteristics. The smallest particle size (56.5 µm) was recorded for the freeze-drying treatment, while boiling followed by oven drying had the largest particle size (307.5 µm). Microstructural results indicate that boiling and blanching at 95 °C, followed by oven drying resulted in damaged starch granules, while freeze-drying and low-temperature blanching (60 °C) maintained the native starch granule. Particle size and the solubility index of potato flour showed strong positive correlation. This study revealed that the pretreatments and drying methods affected potato flour’s physical and microstructural parameters differently, resulting in changes in their functionality.

Physicochemical, structural, and rheological properties of Colombian hawthorn yam (Dioscorea rotundata) flour: a product for food sovereignty

“…3d); the deviation is in the range from 27µm to 43µm (< 10%). Obtained results were lower than those reported for freeze-dried potato our (56.51 to 307.53 µm) [33], roasted Highland Barley Flour (< 150 µm) [34], and amaranth our (380 µm) [35]. The structure and morphological characteristics of the our granules are then affected by the origin, agronomy, and processing conditions of yams prominently due to the distinct characteristics and potential applications.…”

Influence of Different Processing Conditions on Nutritional, Phytochemical, and Physical Properties of Aquatic Fern (Azolla pinnata): A Sustainable Nutrient-Rich Human Food

“…Blanching results in decreasing the porosity and increased the moisture content of treated samples as a result of initial activation of cell wall degrading enzymes, prior to the achievement of blanching temperature. 32 Samples with low density exhibit higher porosity because such powders have small particles that can agglomerate to form a clumpy powder, thus producing more voids between them and studies of Buzera et al 11 also reported that hydrothermal treatments at higher temperatures results in the flour with higher tapped density and lower porosity. Higher values of porosity indicated the presence of a larger number of spaces between the particles, which contain oxygen available for degradation reactions.…”

Chemical and Pasting Properties of Potato Flour (Solanum tuberosum L.) in relation to Different Processing Techniques

“…The Shangi variety, the most preferred in the country, was selected and used for this study. Various pretreatments and drying methods were used to process potato tubers into flour Buzera et al [7], as detailed in Figure 1. For the first batch, the potato tubers were washed, peeled, and sliced into 2 mm thickness before being placed in a deionized water solution containing 5% sodium metabisulfite for five minutes in order to prevent enzymatic browning.…”

“…Due to inadequate, expensive, and unevenly distributed cold store facilities in many developing countries, postharvest loss of potatoes is very high [6]. To reduce postharvest losses, fresh potato tubers can be processed into potato flour [7]. In addition to having a longer shelf life, the flour has lower transportation and storage costs [8].…”

“…The procedure is standard and differs in the pretreatments and drying methods [11]. It has been reported that different methods of pretreatment and drying produce potatoes with different physical, chemical, and functional properties, as reported by various studies [7,12]. Özdemir et al [13] reported that freeze drying preserved the nutritional content of potato flour while improving its solubility and emulsifying properties.…”