High TDF starch made by high temperature steeping of grain

#Fiber is an important nutritional component of the human diet. Currently, nutritionists generally recommend the consumption of at least 25 grams per day of fiber. Such levels of fiber may contribute to gut health, heart health, cancer prevention, and avoidance of other health problems. However, it is estimated that in the average diet in the industrialized world, only about 10 grams per day of fiber is consumed. Therefore, providing high-fiber foods which are appealing to consumers is desired. Dietary fiber consists of the remnants of plant cells, polysaccharides, lignin, and associated substances resistant to hydrolysis (digestion) by the alimentary enzymes of humans.

#In recent years, there has been increased awareness of the role of total dietary fiber (TDF) in human diet. Ingredion Incorporated has technologies to increase TDF in starch products such as NOVELOSE® 330 starch (a RS3-type resistant, nongranular, retrograded starch) and HI-MAIZE® 260 starch (a resistant starch derived from high amylose cornstarch), with 30% and 60% TDF contents, respectively. Haralampu et al. in U.S. Pat. No. 5,849,090 provided a method of heating aqueous slurry of a granular native starch to a temperature sufficient to swell the native starch granules without disrupting the starch granules. The swelled granular native starch is then treated with a debranching enzyme to give a starch with a TDF content from about 20% to about 50% by weight.

#FIBERSYM® RW starch (a food-grade resistant wheat starch) contains a minimum TDF of 85% (dry basis (db)) as determined by AOAC Method 991.43. The production process for FIBERSYM® starch RW involves treatment of wheat starch with sodium trimetaphosphate (a cross-linking agent) and sodium tripolyphosphate (a substituting agent) yielding a highly cross-linked wheat starch containing small levels of substituents. ACTISTAR® RT starch (a resistant modified food starch derived from tapioca) contains about 80 percent TDF. The production process for ACTISTAR® RT starch involves enzymatic de-branching of a tapioca maltodextrin and subsequent retrogradation. Konjac flour comprises a glucomannan and is derived from the tubers of Amorphophallus konjac. Konjac flour contains 85% to 95% TDF. The konjac glucomannan is a high molecular polysaccharide with mannose and glucose residues, which are linked together by β-1,4 linkages in a molar ratio of 1.6:1.0. Acetyl groups along the konjac glucomannan backbone occur on average every 9 to 19 sugar units.

#FIG. 1 depicts the thermal properties of the starch product obtained by the high temperature steeping process of the present application.

#FIG. 2 depicts the comparison of the TDF content of the final starch made by the one step process to the amylose content of the starting corn.

#In one aspect the application provides a starch comprising greater than 70% by weight of total dietary fiber as determined by the AOAC 991.43 test method and wherein the starch has not been chemically modified. In one embodiment the amount of total dietary fiber is between about 70% to about 80% by weight. In another embodiment the amount of total dietary fiber is between about 72% to about 78% by weight. In another embodiment the amount of total dietary fiber is between about 74% to about 76% by weight. In another embodiment the amount of total dietary fiber is between about 72% to about 74% by weight. In another embodiment the amount of total dietary fiber is between about 76% to about 78% by weight. In one embodiment the starch is a grain starch. In another embodiment the grain starch is a corn starch. In another embodiment the starch is prepared by a process comprising: a) steeping high amylose corn kernels at a temperature from about 71° C. to about 93° C. for a time from about 24 hours to about 72 hours; b) subjecting the high-temperature steep corn kernels to conventional wet milling; c) subjecting the recovered intermediate starch to heat-moisture treatment; and d) wherein the final starch comprises greater than 70% by weight of total dietary fiber. In one embodiment the steeping process is done in two stages. In another embodiment the two stage steeping process is done first at a temperature from about 71° C. to about 76° C. for a time from about 14 hours to about 26 hours and done secondly at a temperature from about 76° C. to about 88° C. for a time from about 14 hours to about 26 hours. In another embodiment the two stage steeping process is done first at a temperature from about 71° C. to about 73° C. for a time from about 17 hours to about 23 hours and done secondly at a temperature from about 79° C. to about 85° C. for a time from about 17 hours to about 23 hours. In another embodiment the two stage steeping process is done first at a temperature of about 71° C. for a time of about 20 hours and done secondly at a temperature of about 82° C. for a time of about 20 hours. In one embodiment the steeping process is done in one stage. In another embodiment the one stage steeping process is done at a temperature from about 71° C. to about 76° C. for a time from about 24 hours to about 36 hours. In another embodiment the one stage steeping process is done at a temperature from about 71° C. to about 73° C. for a time from about 27 hours to about 33 hours. In another embodiment the one stage steeping process is done at a temperature of about 71° C. for a time of about 30 hours.

#The present application proposes high temperature steeping of corn kernels, especially high amylose varieties, at temperatures ranging from 71° C. to 93° C. for 24 hours to 72 hours. The high temperature steeped starch kernels are subjected to conventional wet milling process to recover starch. The extracted starch shows increased TDF content, ranging from 33% to 45% as compared to conventional wet milling process, which showed a TDF of 20% to 25% in starch (Table 1). The process has no negative impact on the recovery and quality of extracted starch. The current application describes a simple and economical way to make a starch product with high TDF values that are highly desirable for nutritional applications.

#TABLE 1 TDF summary of the steeping experiments TDF corn Steeping Description (%, db) A7 One step steeping at 49 C. for 20.4 30 h → wet milling → dried starch A7 One step steeping at 57 C. for 22.4 30 h → wet milling → dried starch A7 One step steeping at 71 C. for 31.1 30 h → wet milling → dried starch A7 One step steeping at 71 C. for 29.6 30 h → wet milling → dried starch A7 One step steeping at 77 C. for 38.5 30 h → wet milling → dried starch A7 Two step steeping at 71 C. for 20 h and 35.4 82 C. for 20 h → wet milling → dried starch A7 Four step steeping w/o quenching 45.2 60 C.→71 C. → 82 C. for 64 h → 93 C. 20 h at 93 C.→ wet milling → dried starch A8 One step steeping at 60 C. for 29.1 30 h → wet milling → dried starch A8 One step steeping at 71 C. for 36.4 30 h → wet milling → dried starch A8 One step steeping at 82 C. for 43.9 30 h → wet milling → dried starch A8 Two step steeping at 71 C. for 20 h and 43.4 82 C. for 20 h → wet milling → dried starch A8 Four step steeping w/o quenching 45.2 60 C.→71 C. → 82 C. for 64 h → 93 C. 20 h at 93 C. → wet milling → dried starch