The ever-evolving landscape of enzymic modification in starch processing has ushered in a new era of technological breakthroughs, with a particular focus on the production of cyclodextrins. These intriguing cyclic molecules, comprised of 6-8 glucose units connected by a-1,4-bonds, possess a unique ability to encapsulate other compounds within their cavities. This remarkable trait allows them to stabilize, solubilize, or precipitate various compounds, as elucidated by Pszczola in 1988. The key catalysts for the synthesis of cyclodextrins during starch liquefaction are enzymes classified under the category of cyclodextrin glycosyl transferases (CGTase), as expounded by Nielsen in 1991.
One noteworthy application of enzymic prowess lies in the production of fructose from inulin. Inulin, a linear β-2,1-linked fructose polymer initiated by a glucose unit, is found in the roots of plants like chicory and Jerusalem artichoke. The enzymic hydrolysis of inulin to fructose involves a strategic combination of exo-inulinase (EC 3.2.1.80) and endo-inulinase (EC 3.2.1.7). A notable example is Fructozyme™, a product derived from a specially selected strain of Aspergillus niger, manufactured by Novo Nordisk, as documented by Zittan in 1981 and outlined in the application sheet of 1993.
The extraction of inulin from plant material involves a meticulous diffusion process at elevated temperatures. The resulting raw juice undergoes purification through methods akin to those used in sugar beet processing, including liming and carbonation, followed by decolorization using carbon. For optimal performance of Fructozyme, a dry substance content in the raw juice ranging from 15-25% is recommended. Achieving a degree of hydrolysis exceeding 98% is feasible within a timeframe of 12 to 48 hours, contingent on the enzyme dosage. The resulting fructose syrup can be utilized directly or blended to produce a 55% fructose syrup. Alternatively, the purified syrup serves as a precursor for the production of crystalline fructose, as detailed in the application sheet of 1993.
Enzymatic hydrolysis also plays a pivotal role in the conversion of sucrose to glucose and fructose. Invertase, the enzyme responsible for this transformation, finds application in the confectionery industry, notably in products like ‘After Eight Mints.’ Here, invertase facilitates the conversion of easily crystallized sucrose into a less crystallizable glucose-fructose mixture, transforming the hard sucrose core into the soft center that delights our palates, as revealed by Bains in 1993.
As the intricate dance of enzymes continues to shape the landscape of starch modification, these novel developments hold promise for the advancement of various industries, from food production to pharmaceuticals, ushering in a future where the manipulation of starches becomes an art guided by enzymic precision.