Food or edible material: processes – compositions – and products – Direct application of electrical or wave energy to food... – Heating by electromagnetic wave
Reexamination Certificate
2000-11-28
2003-09-09
Yeung, George C. (Department: 1761)
Food or edible material: processes, compositions, and products
Direct application of electrical or wave energy to food...
Heating by electromagnetic wave
C426S549000, C426S622000
Reexamination Certificate
active
06616957
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to processes for making graham-based flours which exhibit low rancidity and extended shelf-life and to baked goods having a crunchy texture made from such flours. The present invention also relates to reduced fat, low fat, or no-fat baked goods, such as graham crackers and snacks, produced from such flours.
BACKGROUND OF THE INVENTION
Whole cereal grains and graham flour provide a high dietary fiber content but also provide natural lipids and enzymes, such as lipase and lipoxygenase (LPO), which may deleteriously interact during storage. The interaction of the lipids and enzymes can lead to rancidity problems such as off-flavors and odors in baked goods made from graham flour. Generally, to avoid rancidity problems in baked goods, graham flour is employed which is less than about ten days old.
Rancidity in cereal products may be due to hydrolytic (enzymatic) or oxidative degradation reactions, or both. Often, hydrolysis may predispose products to subsequent oxidative rancidity. Nature has provided a number of protective features in seeds to prevent rancidity and spoilage, enabling seeds to survive periods of adverse conditions before attaining an appropriate environment for germination and growth. Rancidity is less likely to develop when lipid materials, for example, seed oil, are unable to interact with reactants or catalysts such as air and enzymes. One protective feature in cereal grains is the provision of separate compartments for storing lipids and enzymes so that they cannot interact.
Milling cereal grains involves breaking down the separate compartments, bran, germ and endosperm, such that the lipid and enzymatic components of the grain are able to interact, greatly increasing the development of rancidity.
One problem with high-extraction flours, that is, those containing substantial amounts of bran and germ, is that they are less stable than white flours. Prolonged storage of high-extraction flours often leads to the development of rancidity. Rancidity includes adverse quality factors arising directly or indirectly from reactions with endogenous lipids, producing a reduction in baking quality of the flour, undesirable tastes and odors, or unacceptable functional properties. A main reason for the development of rancidity in high-extraction flours is the enzymatic degradation of unstable natural oils. Rich supplies of unstable natural oils are contained in the germ portion of grains used to make high-extraction flours. White flours, on the other hand, contain little or no unstable natural oils or fats because they are made from the endosperm portion of grains and are generally substantially free of bran and germ.
Another reason rancidity is a greater problem in products derived from bran and germ-containing flour is that bran and germ contain the enzymes involved in enzyme-catalyzed lipid degradation. One of the enzymes, lipase, causes hydrolytic rancidity in milling products of sound, ungerminated wheat. Lipase is found almost exclusively in the bran component. The other key lipid degrading enzyme, lipoxygenase (LPO), is present almost exclusively in the germ and also is involved in the development of rancidity. Thus, bran-containing flours or graham flours are much more susceptible to the development of rancidity than are white flours which contain little or no bran and germ.
Enzyme catalyzed lipid degradation that occurs in high extraction flour, causing rancidity in such flour, is believed to occur by the action of lipase followed by the action of LPO. When lipase, the enzyme found almost exclusively in the bran portion of the grain, is activated during milling, it reacts with unstable oils naturally occurring in the grain and breaks down the unstable oils to free fatty acids (FFA). This process may take weeks or even months. Then, LPO, the enzyme found almost exclusively in the germ portion of the grain, oxidizes FFA in the presence of oxygen producing volatile breakdown products such as peroxides that, in turn generate rancid aldehydes. In the absence of moisture, oxidation of FFA is also a very slow process and can take up to several weeks until noticeable amounts of rancid aldehydes can be detected. However in the presence of moisture, or water, which is normally added to flour in large amounts during the dough work-up stage, enzyme catalyzed oxidation of free fatty acids tends to proceed to a great extent very quickly causing formation of large amounts of rancid aldehydes in a matter of just a few minutes.
While steam and other heat sources may be used to inactivate enzymes, none have been employed in a manner to provide shelf-stable whole wheat berries and graham flour containing a low degree of gelatinized starch. Heat treatment of whole wheat berries using steam may be employed to inactivate enzymes such as lipase and LPO to provide shelf-stable flours upon milling and/or processing. However, steam heat treatment tends to substantially gelatinize starch in the berries or fails to substantially completely inactivate lipase and LPO. In Bookwalter, U.S. Pat. No. 4,737,371, for example, steam treatment for a 4-12 minute period of time only “significantly reduces” lipase activity but does not substantially inactivate lipase. When steam treating under conditions sufficient to substantially inactivate lipase and LPO, steam penetrates the berries and gelatinizes a substantial amount of starch in the interior endosperm of the berries. The moisture from steam induces gelatinization of starch in the berries, when combined with the heat brought to the interior of the berries by the steam. The excessive moisture which penetrates the berries during steaming also necessitates long drying periods to reduce the moisture content to an acceptable level for milling.
Dough containing highly gelatinized starch contents that result from steam treatments to inactivate enzymes, for example more than 20% of gelatinized starch, tends to be poorly machinable and require additives to improve processing. Additives including sugar are often added to improve the machinability of highly gelatinized graham flour. However, sufficient amounts of sugar needed to improve machinability are generally inappropriate for low-calorie applications, such as reduced fat, low-fat and no-fat crackers.
Whole wheat berries and graham flours having higher degrees of gelatinized starch may be acceptable for applications wherein crunchy baked products are desired. It has been found by the present inventors that crackers made from whole wheat flour having from about 5% to about 20% gelatinized starch obtained using infra-red heating are unexpectedly crunchier than crackers made from whole wheat flour having ungelatinized starch. Likewise, baked goods made from dough containing less than about 5% of gelatinized starch are not as crunchy as baked goods made from dough comprising flours having from about 5% to about 20% gelatinized starch. However, dough containing flour having more than 20% of gelatinized starch, e.g. more than about 25% gelatinized starch, tends to be too short, or not very elastic, and is thus poorly machinable because it tends to break and tear when sheeted.
Another problem encountered with unstable wheat flour is that wax paper packaging or other semipermeable packaging must be used to permit the escape of rancid odors from such products. Metallized film packaging has been avoided for such applications as they do not permit the escape of rancid odors which often accompany unstable whole wheat flour and products. Metallized film packaging is desirable, however, in the snack food industry because of its ability to preserve the freshness of a packaged product and to prevent the product from absorbing moisture and odors. Aesthetics requirements have also led to an increased use of metallized film packaging. Stable flours and baked goods that have long shelf-lives, for example, 45 days or longer, do not require semipermeable packaging because they do not produce sufficient amounts of rancid odor to require continuous release thereof from the pac
Adrianson Tim Michael
Gannon Diane Louise
Howey Edward Douglas
Levine Harold Ira
Mozeke Patricia Ann
Hollander Law Firm, P.L.C.
Kraft Foods Holdings, Inc.
Yeung George C.
LandOfFree
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