Tesis

SENSORY EVALUATION

JOURNAL OF FOOD SCIENCE

Sensory Attributes and Storage Life of Reduced Fat Ice Cream as Related to Inulin Content
L.A. Schaller-Povolny and D.E. Smith

ABSTRACT Effects of substitution of inulin for 42DE (dextrose equivalent) corn syrup in reduced fat ice cream were studied using sensory analysis. Three combinations of inulin and corn syrup were evaluated for iciness,chewiness, sweetness and vanilla flavor intensity. Replacing 50% or 100% of 42DE corn syrup with inulin increased chewiness. However, sweetness and vanilla flavor intensity perception of the ice cream were reduced. Storage stability data showed that partial or full replacement of 42DE corn syrup with inulin inhibited ice crystal formation over a 6-wk thermal abuse period. Key Words: ice cream,inulin, corn sweeteners, sensory evaluation

INTRODUCTION
SWEETENERS HAVE TWO PRIMARY FUNCTIONS IN AN ICE CREAM product: (1) increase sweetness and (2) increase viscosity and total solids improving texture (Marshall and Arbuckle, 1996). Sucrose, corn syrups and high fructose corn syrup (HFCS) are principal sweeteners used in ice cream. In many frozen dairy desserts the total amount of sweetenerranges from 12–16% (w/w) with 25% or more comprised of corn based sweeteners. Addition of corn syrups contributes to a desirable texture and chewiness (Keeney and Kroger, 1974). High dextrose equivalent (DE) corn sweeteners have a lower average molecular weight than sucrose thus the freezing point of the mix is depressed more when they are used. A mix with a lower freezing point has less waterfrozen as the ice cream exits the freezer. This reduces the storage life of the product because it is more susceptible to increases in ice crystal size during temperature fluctuations (Baer and Czmowski, 1985; Peterson, 1992). Use of higher molecular weight (low DE) corn syrups impart protection against development of coarse textured ice cream during storage since the freezing point is depressed to alesser extent (Keeney and Kroger, 1974; Hagiwara and Hartel, 1996). Fructooligosaccharides (FOS) or inulin comprise another group of carbohydrates with structures similar to corn sweeteners. These are nondigestible oligosaccharides comprised of fructans linked by (21) glycosidic bonds, with one end of the molecule occupied by a -Dfructose or an -D-glucose (Roberfroid et al., 1993; Spiegel et al.,1994). Inulin is a naturally occurring storage oligomer found in plants such as chicory and Jerusalem artichoke and has a degree of polymerization of 2 to 60. Inulin modifies the microflora of the human colon, resulting in health benefits for the host (Yamashita et al., 1984; Gibson et al., 1994, 1995; Tomomatsu, 1994). Inulin is a prebiotic food ingredient, defined by Gibson and Roberfroid (1995)as: “a food ingredient that is nondigestible by humans and beneficially affects the host by selectively stimulating the growth of a limited number of
The authors are affiliated with the Dept. of Food Science & Nutrition, Univ. of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108. Address inquiries to Dr. D. E. Smith.

bacteria in the colon, so that the end result is the improvement of the host’shealth”. Inulin is resistant to digestion by mammalian small intestinal enzymes such as -amylase, sucrase and maltase, but is selectively utilized by specific colonic bacteria, Bifidobacteria and to a lesser extent Lactobacilli (Oku et al., 1984; Gibson et al., 1994; Briet et al., 1995; Knudsen and Hessov, 1995). Bifidobacteria produce an enzyme ( -fructosidase) that can break down inulin and thusallow it to be utilized by the organism. The result of this hydrolysis and fermentation is the lowering of pH in the colon and an increased production of short chain fatty acids (SCFA) such as acetate, L-lactate, propionate and butyrate (Delzenne and Roberfroid, 1994). Interest has increased in the survival and stability of Bifidobacteria incorporated into dairy products such as ice cream,...