Innovation in Tigernut (Cyperus Esculentus L.) Milk Production: In Situ Hydrolysis of Starch

Abstract

Tigernut tubers (Cyperus esculentus) are used for the production of vegetable milk, commonly known as “Horchata de chufa” in Spain. The presence of starch in the tuber limits the yield of the milk, since this carbohydrate gelatinizes during the pasteurization of the milk and leads to the considerable solidification of this drink. The present work aims to improve the yields and extraction practice of the milk by an in situ hydrolysis of starch, using exogenous amylases of industrial or vegetable origin. The obtained results show that sprouting improves the extraction yields of tigernut milk, which goes from 50% to about 70%. This improvement in milk yield corresponds to a hydrolysis of about 35% of the starch in the tuber. The use of exogenous amylases leads to starch hydrolysis rates of 45% and 70%, respectively, for amylolytic extracts from sprouted tigernut tubers and amylase, with the corollary of a natural increase in the sweetness of milk. This technical approach makes it possible to produce a naturally sweetened tigernut milk which easily lends itself to pasteurization without a significant increase in viscosity.

The Influence of Soaking and Sprouting on the Physicochemical Characteristics of Tigernut Tubers (Cyperus esculentus L.)

“…In African nibbling practices on tigernut tubers, they undergo treatments, such as roasting and soaking, in order to soften them. The starch content (30-40%) of tigernut tubers constitutes one of the main production limits for vegetable milk as it can contain nearly 18% of this polysaccharide after its extraction and grinding [2][3][4]. As a result, tigernut milk (horchata) is not easily suitable for pasteurization, due to the risk of gelatinization of this starch [4,5].…”

“…The starch content (30-40%) of tigernut tubers constitutes one of the main production limits for vegetable milk as it can contain nearly 18% of this polysaccharide after its extraction and grinding [2][3][4]. As a result, tigernut milk (horchata) is not easily suitable for pasteurization, due to the risk of gelatinization of this starch [4,5]. So, horchata production requires either the removal of pasteurization, leading to a reduction in its microbial stability, or to the elimination of the starch by decantation before pasteurization, leading, this time, to a loss of its nutritional value [4,6,7].…”

Enriching Tiger Nut Milk with Sodium Caseinate and Xanthan Gum Improves the Physical Stability and Consumer Acceptability

“…Formation of starch granules at the buttom layer of TNM was previuosly reported (Codina-Torrella, Guamis, Ferragut, & Trujillo, 2017;Djomdi et al, 2020). This instability and the sub-optimal flow properties of TNM are known to adversely affect consumer acceptance of TNM and related products (Dhankhar & Kundu, 2021;Kizzie-Hayford et al, 2021;Kizzie-Hayford, Jaros, Zahn, & Rohm, 2016;Sanful, 2009) which therefore need improvement.…”

Tiger Nut (Cyperus esculentus L.): Nutrition, Processing, Function and Applications

“…Tiger nut contains a high amount of starch that is easy to gelatinize during the pasteurization process, leading to the coagulation of the milk and limits the output. Exogenous amylase can be used to increase the yield through the in situ hydrolysis of starch, which is a process that increases the sweetness of milk and is suitable for the industrial production of tiger nut milk [ 67 ]. In addition, heat treatment could cause the loss of nutrients such as the total protein, phenols and vitamins of the tiger nut milk.…”