Starches spark frozen food development
February 16, 2010
by Jeff Gelski
T rends in convenience and eating at home have boosted the frozen foods/microwave category recently. Starches have played a role in improving the quality of those products, and it is a good bet they will have a hand in any future innovation. For example, certain starches may assist in a move to “clean” labels, and other starches may help to light a spark in the sale of frozen entrees featuring meat.
“Starch may be the most important ingredient in microwave foods,” said Celeste Sullivan, technical manager in food applications for Grain Processing Corp., Muscatine, Iowa. “It functions as the primary thickener in dry food mix soups, sauces, gravies, entrees including meat and bakery products.”
Shana Brewer, senior marketing analyst of Savory Products for National Starch Food Innovation, Bridgewater, N.J., said starches play an important role in providing both texture and temperature stability through the refrigeration, freezing, thawing and heating steps typically encountered by a ready meal.
Modified food starches offer several benefits.
“Modified starches work best to provide consistent viscosity and stability against pH and shear and ice crystal damage during frozen storage,” said Mark Purpura, technical service manager for Advanced Food Systems, Inc., Somerset, N.J.
But companies seeking to make products with simpler labels or all-natural claims may want to avoid using modified food starches, said Dianna Briceno, marketing manager of Wholesome for National Starch Food Innovation.
“We have a technology that allows us to physically treat our starches to make them as functional as chemically modified food starch,” she said.
The company’s Novation product line of functional native starches includes waxy maize, tapioca, rice and potato bases. The Prima products in the line add freeze/thaw and cold storage stability. National Starch also offers a HOMECRAFT family of specialty flours that provide the “viscosifying” power and stability of modified food starches while offering the opacity and home-style textures typically seen from flour, Ms. Brewer said.
While native starches may be used in the development of clean label products, they often have less stability and are more affected by heat, pH and ice crystal damage during freezing, Mr. Purpura said.
Gums and/or hydrocolloids may be added to a starch/gum blend to make the product more tolerant. Advanced Food Systems often uses a starch/gum blend in its Actoloid, Actobind, Actoglaze and other ingredient systems because the blend allows the best stability and the cleanest flavor release, Mr. Purpura said.
Overall, the frozen foods department had sales of $40,429,915,266 for the 52 weeks ended Dec. 26, 2009, up 3% from $39,129,462,101 in the previous 52-week period. The statistics covered U.S. food, drug and mass merchandisers, including Wal-Mart Stores, Inc. Sales of frozen pizza were $4,165,517,732, up 9% from $3,838,556,608 in the previous 52 weeks.
Yet sales of frozen entrees with meat declined 2% to $1,089,335,894 from $1,113,992,125 in the previous 52-week period, according to Nielsen. Grain Processing Corp.’s Pure-Cote product may prove beneficial in meat products, Ms. Sullivan said.
“Meats often become tough and rubbery in the microwave,” she said. “Forming an invisible ‘skin’ or surface coating on the boneless, skinless chicken breast or pork loin using Pure-Cote, modified food starch, will allow for a more moist and tender finished product. It helps to retain moisture and increase yield. It also functions as a means to carry flavors, heat activated caramel colors or adhere spices.”
Rice starches commonly are used in meat marinades to improve yield, hold moisture and add succulence, Ms. Brewer said. Rice starches offer a clean and bland flavor profile, she said. Waxy rice starch in particular offers inherent freeze-thaw ability. Potato starches, when used in meat products, allow companies to remove some of the phosphates, which may lead to a cleaner label, Ms. Brewer said.
Sauces may bring their own problems to frozen/microwavable meals.
Temperature cycling may be detrimental to a meal system, causing negative changes to occur, such as gelling and syneresis in sauces, and moisture loss in the protein portion, Ms. Brewer said. In addition, the starch needs to be able to withstand the heat from the reconstitution step, typically in the microwave or oven, for the sauce to remain thick and creamy, she said, and the meat to maintain its succulence and juiciness at the consumer level.
In the case of Salisbury steak and gravy, the gravy, after freezing and thawing, might be gelled with a traditional flour or unmodified starch, Ms. Brewer said.
“Formulating with modified starches would help maintain the ‘flow-ability’ of it, the smoothness, textural uniformity,
and desired viscosity after heating,” Ms. Brewer said.
Handling moisture is always important in the microwave/frozen category. Grain Processing Corp.’s Pure-Gel modified food starches begin to hydrate in the range of 120 degrees Fahrenheit, allowing for the early penetration and uniform heating in the microwave oven, Ms. Sullivan said.
“This lower gelatinization temperature reduces ingredient settling and stratification in the mix,” she said. “This feature helps to bind the moisture early, often eliminating the need for frequent stirring. It also improves the overall flavor and texture due to less moisture evaporation.”
Studying starch attributes
Recent scientific studies on food starches have focused on sensory properties, glycemic index and appetite.
Comparing five starches
A study appearing Jan. 29 on-line in the Journal of Food Science examined the effect of five types of starches (rice, potato, waxy corn, corn and modified waxy corn) on the sensory properties of white sauces. The rice and modified starches presented similar behavior to each other, as did the potato starch and corn starch. The waxy starch showed the most resilience. The freeze/thaw cycle had the greatest effect on the sauce with corn starch and increased its graininess and heterogeneity values owing to retrogradation.
A comparative study examined variations resulting from freezing/thawing and the effect of replacing 0.15% starch with two non-starchy hydrocolloids in xanthan gum or locust bean gum in samples to be frozen. Lower graininess and heterogeneity values were observed in the sauce made with corn starch. In the reheated sauces made with rice, potato or waxy or modified starch, adding xanthan gum or locust bean gum did not have a significant effect on sensory attributes.
The authors of the study work at the Inst. De Agroquimica y Tecnologia de Alimentos (CSIC) in Spain.
An effect on glycemic response
A study performed at Kansas State University showed Fibersym RW, a resistant wheat starch, is effective in developing food products with a lower glycemic and insulin response. The study, published on-line in the Journal of Nutrition and Metabolism, involved 13 healthy adults. They were fed two nutritional bars, as well as a control glucose drink, after a 12-hour overnight fast. Puffed wheat was in one bar. Fibersym RW replaced puffed wheat in the other bar. Both glucose and insulin were monitored over a 2-hour period after the samples were consumed.
“Both peak and incremental areas under the curve for glucose and insulin were significantly lower following ingestion of the bar containing Fibersym RW compared to the puffed wheat bar and control glucose drink,” said Mark Haub, associate professor of the Department of Human Nutrition and director of the metabolism laboratory at K.S.U. in Manhattan. “One surprising and useful outcome of the study was that Fibersym RW significantly attenuated the glycemic and insulinemic responses even when high-glycemic ingredients such as brown sugar and corn syrup represented 31% of the nutritional bar formula.”
MGP Ingredients, Inc., Atchison, Kas., offers Fibersym RW.
Results of a study appearing in the British Journal of Nutrition suggest consuming 48 grams of resistant starch over a 24-hour period may be useful in managing the metabolic syndrome and appetite. The acute randomized, single-blind crossover study involved researchers at the University of Surrey.
Twenty healthy adult males consumed either 48 grams of resistant starch or a placebo divided equally between two mixed meals on two separate occasions. A significant lower energy intake followed the resistant starch supplement compared to the placebo. Postprandial plasma glucose concentrations were not significantly different, but a significantly lower postprandial insulin response followed the resistant starch supplement.
The study used Hi-maize resistant starch from National Starch Food Innovation, Bridgewater, N.J.