Sugar Profile of Syrups from Malted and Unmalted Rice of Different Varieties

Abstract

Rice syrup was produced from ten varieties of locally available rice in Nigeria. Flours of malted and unmalted rice from different varieties were treated with a combination of starch hydrolyzing enzymes (Amyloglucosidase, Bacterial α-amylase and Fungal α-amylase); and the starch hydrolysates were either filtered and/or centrifuged at the end of hydrolysis. The resulting rice syrup was evaluated for sugar compositions (maltose, glucose, maltotriose, sucrose, raffinose and stachyose) using HPLC. The results showed that syrups from malted rice had significantly higher (p<0.05) maltose and maltotriose concentration than syrups from unmalted rice. The resultant syrup is a ‘High Maltose Syrup’ since maltose was found to be the predominant sugar in the rice syrup with concentration of above 50% especially for malted samples. Rice syrup can be widely applied as a potential raw material in beverage and confectionery industries as well as a good adjunct for brewing since the sugar profile of the rice syrup was similar to that of barley wort.

Functional properties of syrup from malted and unmalted rice of different varieties: A comparative study

“…The schematic diagram for production of rice syrup from malted/unmalted rice, is presented in Figure 2, consistent with that previously described by Ofoedu et al. (2019). As shown, the production of syrup constitutes of a number of slurry stages of rice (malted/unmalted) hydrolysis, up to filtration (Whatman No.…”

“…Syrup with DE >38 portrays high content of fermentable sugars, which can enhance beer brewing (Dziedzic & Kearsley, 1995). Increased maltose and/or maltotriose content produced during malting (Goldhammer, 2008; Palmer, 2009), might be accounting for the lower DE in malted samples (Ofoedu et al., 2019) where it occurred in the current study. Herein also, centrifuged syrup obtained higher DE ( P < 0.05) compared to filtered ones.…”

“…Higher DE suggests more starch is hydrolyzed with corresponding quantity of reducing sugars (Van der Poel et al., 1998). Higher DE of rice syrup herein also suggests more glucose molecules were potentially present in the unmalted compared to the malted group (Ofoedu et al., 2019). Syrup with DE >38 portrays high content of fermentable sugars, which can enhance beer brewing (Dziedzic & Kearsley, 1995).…”

“…Rice varieties were malted using barley malting procedure described by Ofoedu et al. (2019), which aimed to prepare rice varieties for syrup making. Briefly, rice (paddy) grains were steeped in the ratio of 1 kg paddy rice to 5 L of potable water at room temperature (20 to 25 °C) for 36 hr with alternating steep cycle of 12 hr wet‐steep period and 45 min air rest.…”

“…Furthermore, rice converted to malt can bring about useful products, for example, beer, flavored drinks, malted milkshakes, and syrup (Osuji, Ofoedu, & Ojukwu, 2019). During syrup production, rice malt can enhance aroma, color, sugar profile, and other quality characteristics, which is largely desirable by end users (Ofoedu, Osuji, & Ojukwu, 2019). Besides a solution of dissolved sugars or hydrolyzed starch, syrup represents a thick viscous liquid of dissolved saccharides slightly able to deposit crystals (Hull, 2010; IFIS, 2005).…”