WO1996002149A1

WO1996002149A1 - Food mixtures comprising legume with low fat absorbtion upon frying

Info

Publication number: WO1996002149A1
Application number: PCT/US1995/008706
Authority: WO
Inventors: Israel A. Saguy; Pnina Weinberg; Eli Pintus
Original assignee: Yissum Research Development Company Of The Hebrew University In Jerusalem
Priority date: 1994-07-15
Filing date: 1995-07-12
Publication date: 1996-02-01
Also published as: IL110338A; IL110338A0; EP0798969A4; EP0798969A1; AU3007095A

Abstract

The invention provides novel foods comprising from 1 % to 10 % by weight of ground legume together with from 0.2 % to 1.5 % of GRAS salt, the balance being conventional food mixtures. Upon frying the foods of the invention the oil uptake is significantly reduced compared with the oil uptake of the conventional food products not containing legume. Chick peas and lentils are the preferred legume of the invention.

Description

FOOD MIXTURES COMPRISING LEGUME WITH LOW FAT ABSORBTION UPON FRYING

Brief Description of the Invention

The invention relates to novel food mixtures. More particularly, the invention concerns food mixtures which upon frying absorb a relatively small amount of oil.

Background of the Invention

Fats and oils have a unique universal appeal. As yet, they have not been matched in functionality by any other food component. They offer unique properties that includes flavor and smooth mouthfeel, improving the overall food palatability. Deep-fat frying is a very important process in modern food preparation, utilized widely by both the food industry and consumers. Numerous processed foods are prepared by deep-fat frying. One of the most important quality parameters of those products is the amount of fat absorbed during the frying process. Recent consumers' trend toward healthier foods is creating significant pressure to reduce the amount of fat in the end-products. Despite such market forces, fried food products still contain huge amounts of fat, often reaching in some cases 49% of the total product.

A wide spectrum of factors has been reported to affect oil uptake, including oil quality, frying temperature, duration of frying, product shape, its content (e.g., moisture, solids, fat, protein), porosity, pre-frying treatments (e.g., drying, blanching) and coating, as reviewed by Selman and Hopkins, in Tech. Memorandum 475. Campden Food & Drink Res. Assoc. Chipping Campden, Gloucestershire, U.K., 1989. Gel-strength was proved to be another significant factor which affects oil uptake as described by Pinthus et al., 1992 in J. Food Science 57: 1359-60. Duxbury, D.D. in Food Proc. 50(2):66, 1989 shows that batters and breadings can influence oil absorption. US Patent no. 5,019,409 discloses that the incorporation of long-fiber cellulose into batters or donut mixes reduces oil uptake during deep-fat frying. Also, methocel was found significantly more effective than powdered cellulose in reducing the amount of oil uptake as described by Pinthus, E.J., Weinberg, P. and Saguy, I.S. in J. Food Science 58: 204-205,222, 1993.

Initial and final water content has a major impact on the amount of oil uptake during deep-fat frying of foods. As water retention is strongly affected by some food additives, the addition of algi nates or cellulose could play a major role in changing the amount of oil uptake and moisture loss during deep-fat frying as explained by Duxbury 1989, ibid.

US Patents nos. 5,021,248, 5,126,152, 5,145,702, 5,182,130 and 5,217,736 describe methods of reducing oil uptake by coating the foods, prior to frying, with an edible oil barrier film created by prolamines proteins. It has been disclosed, such as by Mathur et al., 1968. Ind Jour Med Res 56(6): 863-866, that prolamine proteins are non-existent in legumes (e.g., Bengal gram, Cicer arietinum), or their concentration is very low.

US Patent nos. 5,100,684 and 5,192,572 describe a method of preparing potato pieces such as potato slices, french fries, potato cubes and potato skins, with a lower fat content by frying the potato pieces in oil comprising from about 0.5% to about 2 % of a hydrophobic, or a hydrophilic silica.

Proteins such as soy flour, or gluten are known to reduce fat absorption in foods undergoing deep-fat frying. Yet, the mechanism by which this occurs is unclear. The utilization of soy flour in cake donuts to reduce fat absorption was reported in the literature by Martin and Davis, Cereal Chemistry 63(3):252-255, 1968 and by Wolf, J.W., J. Agric, Food Chem. 6:969, 1970. When such proteins are added to the basic formula of a food product, high quality proteins are used. Although these proteins may be available commercially, high purity and specific physical properties are required, which significantly affect their price, which may be prohibitive for regular usage.

Several other patents relate to decreasing of oil uptake in fried foods. Japan patent publication no. 3,143,344 discloses deep fried food products, such as doughnuts, containing bean curd in dough wherein oil absorbtion is significantly reduced. It is reported that 5-100% of bean (in case of powder bean 1-60%) is contained. Japan Patent publication no. 2,020,258 describes bread crumbs with low oil absorption, said crumbs are pulverized of bread made of dough containing fibre cell membrane from bean extract, wheat flour, water, yeast and other additives (e.g. edible salt, glucose, or oil and fat).

Summery of the Invention

It is the object of the present invention to provide a method for decreasing the oil uptake during frying of foods.

It is a further object of the present invention to provide food mixtures with additives which decrease the amount of oil absorbed during frying compared with the amount of oil absorbed in frying of similar food mixtures which do not contain said additives.

In accordance with the present invention there are provided food mixtures for producing fried food products comprising from 1 % to 10% by weight of ground legume together with from 0.2% to 1.5 % of GRAS (generally recognized as safe) salts, the balance being conventional food mixes, not containg legume.

It has been surprisingly found in accordance with the invention that the addition of between 1 % to 10% of legume together with between 0.2% to 1.5 % of GRAS salt to conventional foods significantly reduce the oil uptake upon frying. Thus upon frying the food mixtures of the invention, the oil uptake is significantly reduced compared with the oil uptake of the conventional foods which form the balance in the mixtures of the invention.

It has been further found that the interfacial tension of the food mixtures according to the invention is higher than the interfacial tension of the corresponding conventional food mixes, which do not contain between 1 % to 10% legume. Thus, the change in the interfacial tension, resulting probably from the formation of a hydrophilic film on the food product, provides the physical explanation for the surprising effect of legume in the presence of salt, on the oil uptake of conventional foods.

It has been further found that the initial porosity of the food mixtures according to the invention is lower compared to the corresponding conventional food mixes, which do not contain legume. This reduction in initial porosity is increasing during the frying process. Thus, the change in the porosity, resulting probably from the formation of a hydrophilic film on the food product, increases interfacial tension and on the other hand, reduces porosity. This provides an explanation to the surprising effect of legume in the presence of salt, on oil uptake of conventional food.

Conventional foods are any foods including natural foods, e.g. fresh potatoes, vegetables, fish and meat, reconstructed food, e.g. croquettes, potato waffles, potato savories, and pancakes, engineered foods, e.g. onion rings and corn or potato snacks and coated foods, e.g. battered and breaded fish, vegetable, or meat. When referring to coated foods, the mixtures of the invention relate to the coating per ce, e.g., to the batter, the breading or the like. The legume and salt may be added to the food mix at any stage of the preparation thereof. Thus, when preparing a coating according to the invention the legume and salt may be added to the coating at the final stage of the preparation of the coating, or at a preliminary stage; e.g., preparing the raw material for coating by adding legume and salt to the flour mixture used for baking bread, which is subsequently used for the production of bread crumbs.

The salt added to the mixtures of the invention may be any food acceptable GRAS ("generally recognized as safe", as defined by the FDA) salt, preferably NaCl.

The legumes are any material selected from the family Leguminosae, which includes over 12,000 species in about 500 genera. Of these, only few are of economic value as foods, e.g., peas, beans, chick pea, lentils, peanuts and soybean. The perfered legume added to the conventional foods are chick pea and lentil.

The mixtures of the invention may be used as dry or as wet mixtures.

The mixtures of the invention may undergo frying in various forms and shapes and can be used for the coating of other foods which undergo frying, the coating can be in the dry form such as crumbs for breading, or moist such as a batter.

The invention extends also to the food mixtures of the invention which undergo frying and to a method for decreasing the oil uptake of foods during frying. Thus, fried food products containing between 1 % to 10% legume are within the scope of the invention.

Detailed Description of the Invention

The invention is described in more detail by the following non-limiting examples:

Example 1

Effect of Chick Pea and Salt on Oil Uptake of Restructured Potato Product

A restructured potato product mass was prepared from the following ingridients: Potato flakes (Idaho), 230 g; Water, 753 g; Alginate (Manugel DMB, Kelco, San Diego, CA), 6 g; Calcium sulphate dihydrate (Terra Alba F+P Grade U.S. Gypsum), 4.5 g; and Tetrasodium pyrophosphate (FMC, Philadelphia, PA), 1 g. To this basic formula chick pea powder, prepered as described below, and NaCl were added as stated below.

The restructured product was prepared as follows: The alginate solution was dissolved in water utilizing a high speed Ultra Turax. The alginate solution and the potato flakes were added to a mixer bowl, mixed for one minute in a Hobart kitchen mixer at speed " 1", and 1.5 min on speed "2". The remaining dry ingredients were added and mixing continued for another 1.5 min on speed "2. " Chick pea powder was added to the potato flakes and was dry mixed thoroughly to assure homogenous mass. The weight of the chick pea used is specified for each experiment. The exact weight of chick pea was subtracted from the potato flakes basic formula, thus the total weight of the sample remained constant. The mass was transferred to a bench scale "hot dog" 9 L extruder (CGT Misanoa, Italy) and extruded into synthetic casing sleeves, 22 mm diameter. The external sleeve was soaked in tap water for ca. 10 min before extrusion.

The filled sleeves were kept at ambient temperature (25 ± 2°C) for 90 min, before freezing at -20°C. The samples were kept frozen until evaluated. Prior to frying, the sleeves were allowed to defrost at ambient temperature, cut to cylindrical pieces, 27 mm length yielding ca. 8.3 g. The synthetic sleeve was carefully removed and the restructured potato cylindrical pieces were left at ambient temperature for an additional 15 min. The average temperature of the samples prior to frying was 16 ± 2°C. Samples were fried in a bench-top deep-fat fryer (12 cm depth) containing 2.5 liters of soy oil at 170 °C. The oil was preheated for 2 hr to break it in prior to frying as described by, Blumenthal, M.M., in Food Technol. 45(2):68-71, 1991, and discarded after 6 hr. Samples were fried for 5 min, removed from the frier and allowed to cool to room temperature, while being wiped on a paper towel.

Chick pea (Cicer arietinum) was prepared as follows: 200 g, were soaked overnight in 800 mL distilled water containing 0.46 g NaHCO₃. The chick pea were washed with tap water, and dried on a paper towel. Then a food processor (Moulinex, France) was utilized for 1 min to εrind the seeds. The chick pea were left at ambient temperature to dry and a coffee grinder (Krups 75, Germany) was utilized for size reduction. The powder passing through a 0.71 mm sieve (25 Mesh) was utilized. Various levels of chick pea and salt were tested. Fat Analysis is based on Method 28.074. In: "The Official Methods of Analysis", 14th ed., AOAC, Arlington, VA. A Soxhlet extraction (AOAC, 1984) of the dried samples was utilized. A mass balance taking into consideration the sample solids and moisture before and after frying was also carried out. This method was calibrated against the Soxhlet extraction.

All analyses were carried out on 4 to 6 replicates.

The effect of added chick pea and salt is summarized in

Tables 1 and 2 in terms of percentage of oil uptake and oil uptake ratio - U_R wherein the value of U_R expresses the weight ratio between the amount of oil uptake and water removed, as described by Pi nth us etal, 1993, ibid.

Ground samples were oven dried at 105°C for 20 h and -moisture content was calculated from the weight of the dry sample and expressed as percentage.

Table 1 - Effect of chick pea concentration on oil uptake and U U_RR iinn aa rreessttructured potato product (0.5% salt; 5 min frying time)

Chick Pea Oil uptake UR Initial Moisture

(%) (%) (%)

0 11.3 0.58 73.6

1 4.3 0.32 73.8

2 2.8 0.22 74.0

3 1.7 0.14 73.8

5 4.5 0.32 74.8

6 2.3 0.16 73.3

8 2.6 0.17 73.2

Table 2 - Effect of salt concentration on oil uptake and U_R in a restructured potato product (5 min frying time). Salt Chick Pea Oil Uptake u_R Initial Moisture (%> (%) ( )

0 0 18.1 0.69 73.6

0 2 14.2 0.60 73.3

0.25 0 17.0 0.68 73.4

0.375 0 11.7 0.57 73.3

0.5 0 11.3 0.58 73.6

0.5 2 2.8 0.22 74.0

0.7^: 0 20.1 0.75 73.9

These data clearly show that both chick pea and salt had a significant synergistic effect on reducing oil uptake. At 2% chick pea and 0.5% salt, the reduction in oil uptake was more than 84% compared to control (no chick pea or salt added), and more than 75 % compared to samples with 0.5% salt and no chick pea.

Example 2

Comparison between the effect of Chick Pea and Typical Additives on Oil Uptake During Frying of Restructured Potato Product

Restructed potato product as described in Example 1 was utilized to compare the effectiveness of added chick pea to the effectiveness of the following known food addirives: Soy protein, 1 % (Purina 590, Purina, Brussels, Belgium) and Vital wheat gluten - gluten 1 % (Amylum, Aalst, Belgium). The raw materials of above ingredients are available commercially from various suppliers and the desired products are obtained by following various concentration and separation steps impacting their overall cost. It should be noted that 1 % gluten is by far more expensive than 1 % or 3% chick pea.

Table 3 - Effect of chick pea , gluten and soy protein on oil uptake of a restructured potato product during deep-fat frying at various frying times.

Chick Pea Gluten Soy

Time Control 1 % protein (sec) 1 % 2 % 3 % 1 %

Oil" u_R Oil u_R Oil u_R Oil u_R Oil u_R Oil u_R

% % % % % %

10 3.6 0.35 2.2 0.33 1.4 0.33 1.3 0.27 0.5 0.21 0.5 0.18

30 5.9 0.43 4.9 0.39 3.7 0.37 1.8 0.21 1.8 0.23 1.3 0.13

60 6.5 0.33 5.7 0.33 4.0 0.25 1.8 0.13 3.0 0.22 2.1 0.11

180 10.3 0.33 7.8 0.23 4.9 0.18 1.8 0.06 2.5 0.09 3.0 0.11

300 13.0 0.42 10.2 0.24 4.9 0.11 2.8 0.06 2.2 0.06 4.6 0.12

Oil uptake %

The data clearly shows that 2 and 3% chick pea were very effective to reduce oil uptake. The data not only shows that chick pea was effective throughout the frying process, it also shows that it had a similar effect compared to 1 % gluten or soy protein.

Example 3

Effect of Added Lentil and Chick Pea on Oil Uptake of deep-frying of Commercial "Latkes"

Commercial "Latkes" - Potato pancake mix (produced by TELMA, Haifa) and comprising dried potato, potato starch, onion, palm oil, salt, MSG and flavors were prepared by adding 86 g of a commercial mix with 190 mL tap water and 55 g egg. The slurry was mixed in a Kenwood Mixer for 2 min (velocity "2") and 1 min (velocity "3"), and allowed to rest for 5 min. The rested slurry was then rounded into cylinder shapes of 30 mm diameter and 10 mm height and fryed as in the frying process described in Example 1. The frying duration was 5 minutes. Experiments were carried out in 4 to 6 replicates. The effect of addition of various additives to the "Latkes" mixture was measured and the results are summerized in Table 4. When an additive was added, the equivalent weight of the Latkes mix was subtracted to keep the same formula.

These following additives were tested:

1. Methyl cellulose 1 % (Methocel K100M, Dow Corp. Midland, MI).

2. Soy protein, as described in Example 2.

3. Beans 3%. Beans were prepared following the same procedure outlined for chick pea as described in Example 1.

4. Lentil 3%. Prepared similarly to the procedure described in Example 1. (Sieve size used was 18 Mesh = 1000 μ ). Table 4 - Effect of Various Additives on Oil Uptake and U_R in Commercial Potato Latkes (5 min Frying Time):

Additive % Oil uptake u_R Initial Moisture

(%) (%)

Control — 8.9 0.20 71.9

Beans 3.0 11.4 0.26 72.3

K100M 1.0 9.0 0.23 70.4

Soy Protein 1.0 7.7 0.21 71.6

Chick pea 3.0 6.3 0.16 70.6

Lentil 3.0 6.1 0.16 71.6

These data clearly show that both chick pea and lentil are very effective mean to reduce oil-uptake during deep-fat frying of a commercial product. The reduction in oil uptake was more than 29% and 31 % for chick pea and lentil, respectively.

Example 4

Effect of Added Lentil and Chick Pea on Oil Uptake of "home made" as distinguished from commercial Potato "Latkes"

Potato Latkes were prepared using a basic formula of: 112.5g of grinded potatoes (using a kitchen grater; and excess water was removed), 7g mixed fresh egg, 2.81 flour and 0.56g salt (0.5 %). The mix was allowed to rest for 5 min, rounded into a cylinder shape (30 mm diameter x 10 mm height). The frying procedure was as described in Example 1. The frying duration was 5 min. Experiments were carried out in 4 to 6 replicates. When chick pea or lentil was added, the equivalent weight of potato was subtracted to keep the same formula. Due to the natural variability of the potato, each experiment was compared to a control. The control was set as 100% and used as the reference. Results are reported as percent of the control.

Table 5 - Effect of Chick pea and Lentil on Oil Uptake and U_R of deep-fried Potato Latkes (5 min Frying Time; 0.5% salt)

Additive % Oil uptake u_R Initial Moisture (compared to (compared to (compared to control =100%) control = 100%) control =100%)

Control — 100 100 100

Chick pea 2.0 89 84 99

Chick pea 3.0 66 66 98

Chick pea 5.0 113 104 97

Lentil 2.0 76 85 98

Lentil 3.0 98 106 99

Lentil 5.0 96 110 99

These data shows that the optimal range of chick pea was 3% and 2% for Lentil. Chick pea was significantly more effective than Lentil at 3% but less effective at 2%. Optimum conditions of 3% chick pea reduced oil uptake by 34%.

Example 5

Effect of Added Chick Pea on Oil Uptake During Deep-Fat Frying of Donuts

The basic formulation for the preparation of the donuts used in the frying experiments is as follows: Flour, 246.50g; Sugar, 90.00g; Baking powder, 3.25g; Salt, 3.00g; Sodium bicarbonate, 2.25g; Egg 50.00g; and Water, 95.00g. Chick pea was added at 0 to 2%. The flour weight was reduced to account for the added chick pea. The donuts were prepared by mixing the donut formulation which excluded the water and eggs, utilizing a Hobart Kitchenaid mixer at speed "1". Eggs and water were then added and mixed at speed "2" for 105 sec until a thick, uniform batter was obtained. The batter was rolled out on a floured table to a thickness of about 0.8 cm and cut into round pieces of 5 cm diameter. The initial moisture content of the dough before rolling was 34.1 %. As a result of the flowered table and atmospheric dehydration, the moisture content of the donuts after rolling and cutting dropped to 30.1 - 32.7% . Each donut was fried in a 190°C pre-heated bench top deep-fat fryer as described in Example 1. The donuts were fried for 75 sec on each side, removed from the fryer and allowed to cool on a paper towel at ambient temperature. The donuts were fried in 8-10 replicates. The results are summerized in Table 6.

Table 6 - Effect of chick pea on oil uptake and U_R in donuts (2.5 min frying time)

Additive % Oil uptake UR

(%)

Control 0.0 15.1 1.47

Chick pea 1.0 14.6 1.42

Chick pea 1.5 12.2 1.26

Chick pea 1.9 11.5 1.20

Chick pea 2.0 11.3 1.16 Example 6

Effect of Chick Pea on Interfacial Tension

To demonstrate the effect of chick pea on interfacial tension of a food product, the formulation of Example 1 was utilized. Interfacial tension was derived from the equation developed by Pinthus and Saguy (1994) J. Food Sci. 59(2): (in press):

r_sI = ~- [1 - Cos (θ_e)]² 4

Where: θ_e - contact angle at equilibrium; r - surface tension (dyne/cm); s - solid; and 1 - liquid.

Liquid surface tension (r,) was determined at room temperature on a Tensiometer (Lauda, Konigshofen, Germany), using the De Nouy method [DIN (Deutsches Inst. fur Normung eV, Berlin, Germany) #53914, 1980.]. The equilibrium contact angle (θ_e) between the frying media and the sample were measured on a Goniometer (NRL CA. Model 100; Rame-Hart Inc., N.J.). The restructured potato product cylinders were peeled from the casing sleeves and allowed to equilibrate to room temperature for 15 min prior to measurement. It is worth noting that shorter equilibration periods resulted in inconsistent results. The equilibration period allowed for the sample external surface to reach a dryness which ensured reproducible results. Droplets of 0.1 ml liquid were deposited with great care from a pipette. The equilibrium contact angle was read several times on both sides of at least 3 drops. The values reported are mean values with a standard deviation of about ± 3°. The contact angle did not vary for about 2 minutes during the measurement. The effect of added chick pea on the intial interfacial tension between the food and the frying medium is demonstrated in Table 7.

Table 7 - Effect of added chick pea on interfacial tension (measured at room temperature)

Additive Interfacial tension - τ_gl (dyne/cm)

Chick Pea Salt

(%) (%)

0 0 0.2

2.0 0 0.09

0 0.5 0.41

2.0 0.5 1.27

3.0 0.5 1.88

6 0.5 1.99

8 0.5 2.11

Table 7 clearly shows that the addition of chick pea together with salt to a reconstructed potato product, increases the interfacial tension of the product, possibly therby, decreasing the oil uptake of the fried product.

Example 7

Effect of Chick pea fractionation on oil uptake

Fractionation of chick pea was obtained by mixing chick pea prepared as in Example 1 in ethanol- (70%). This was done to test the possibility that residual concentration of prolamines that normally are known not to exist in chick pea, may still have some residual effectiveness. chick pea (50 g) were dissolved in 500 mL of 70% alcohol at 40 °C for 2 h; the alcohol was filtered and both the precipitate and supernatant were vacuum-dried. The dried products were added separately to a restructured potato product (described in Example 1) at an equivalent of 2% initial chick pea based on the dry formula of the restructured potato. Oil uptake of the supernatant was 23.0% and a U_R of 0.78 compared to 2.8% oil uptake and a U_R of 0.22 in the control. Simultaneously, the oil uptake of the precipitate prepared according to the same procedure was 15.4% oil uptake and the U_R was 0.63.

Table 8 - Effect of chick pea fractionation on interfacial tension

Additive Interfacial tension - τ_a (dyne/cm)

Chick Pea Salt

(%) (%)

2.0^« 0.5 0.16

2.0^b 0.5 0.1

Chick pea was precipitated with ethanol

Chick pea was precipitated with ethanol and only the supernatant was used.

The above data clearly show that both the precipitant and the superantatant obtained when chick pea was dissolved in ethanol 70% were not effective in reducing oil uptake during deep-fat frying. The data also show that the fractionation increased significantly oil uptake. Thus, it was concluded that chick peas do not contain prolamines, the alcohol (70%) treated chick pea significantly increased oil uptake of a restructured potato product, both the supernatant and the precipitate affect negatively on oil uptake, and the effect of chick peas is therefore unrelated to prolamines. Example 8

Effect of Chick Pea on Oil Uptake of Breaded Fish

Frozen fish (Hake) was placed for overnight in a refrigerator for thawing. Excess water was removed, and the fish was cut into slabs (ca.3.5 x 3.5 x 1.0 cm). Egg mixture was prepared by adding 6.6ml salt (NaCl) solution (25 %) to 55 g fresh egg. The egg mixture was whipped with a fork until a homogeneous mixture was obtained. The egg mixture was let to rest for

2 min. The fish slabs were dipped into the egg mixture for 30 s. The fish was then placed on a screen allowing excess egg to drip off before it was transferred to a plastic bag containing bread crumbs coated with chick pea, wherein the chick pea constituted 5% of the total weight of the breading. The coated bread crumbs were prepared as follows: 1.5 g chick pea powder (prepared according to Example 1) was dissolved in

3 ml. tap water containing 0.0075 g salt (0.5% of the breading), 28.5 g commercial breading were added and the slurry was dried at room temperature. Afterwards, the fish was coated with the bread crumbs containing 5% chick pea. The breaded fish was removed from the bag, excess breading was removed and the fish was fried. Frying conditions were: 170°C for 5 min. The fish slabs were turned from one side to the other in the fryer after 2.5 min to ensure equal frying. The oil was treated as explained in Example 1. The control contained no chick pea (i.e., 30 g bread crumbs), and prepared as described above. The results obtained (average of

4 replicates) are shown in Table 9. Table 9 - Effect of added chick pea on oil uptake of breaded fish.

The data clealy shows that a significant reduction in oil uptake and U_R were obtained, when 5 % chick pea was utilized to coat the bread crumbs.

Example 9

Effect of Chick Pea on Oil Uptake of Battered Fish

Frozen fish (Hake) was thawed and cut into slabs as outlined in Example 8. The control batter was prepared as follows: Egg mix: to a fresh egg (55 g), 0.4 g salt (dissolved in 6 ml. tap water) was added and the mixture mixed with a fork, and let to rest for 10 min. Wheat flour (20.0 g), was then added and the batter was mixed thoroughly with a fork until a homogeneous batter was received. The fish cubes were dipped into the batter until full coverage was obvious. The batter containing chick pea was prepared as follows: 2.4 g chick pea was dissolved in 5 ml. tap water containing salt, the final content of chick pea and salt in batter being 3% and 0.5% respectively. The slurry was allowed to rest for 10 min. The slurry and 1 ml. additional tap water were added to fresh egg (55 g), mixed with a fork, and let to rest for 10 min. Wheat flour (17.6 g) was added and the batter was prepared as outlined above. The battered fish was placed on a screen allowing excess batter drip off before frying. Frying conditions were as outlined in Example 9. The results obtained are shown in Table 10. Table 10 - Effect of added chick pea on oil uptake of battered fish.

The data clearly shows a significant reduction in oil uptake at chick pea content of 3 % .

Example 10

Effect of Chick Pea on Porosity and Oil Uptake

Restructured potato product without and with added 3% chick pea, together with 0.5 % NaCl, as described in Example 1, was utilized to elucidate the effect of chick pea on product porosity and oil uptake. Porosity is defined as: "the volume fraction of the air or the void fraction in the sample' and is expressed as follows:

Porosity = 1 - p_b/p_s

Where: P_t, - Bulk density p_s - Particle density.

Particle density was measured on a Multi-Pycnometer (Quantachrome, Syosset, NY), bulk density was calculated from the sample weight divided by bulk volume, which was determined as volume of glass beads 100 χ displacement. Table 11 Effect of added chick pea on restructured potato product porsity.

The above data clearly shows that added chick pea has a significant effect of reducing the porosity of the restructured potato product. It also shows that the reduction of the porosity in the product containing chick pea increases with frying time.

To demonstrate the importance of product initial porosity on oil uptake as measured by U_R, the restructured potato was stored at fluctuating sub-freezing temperature of -16±2°C and storage duration was up to 21 days. Samples were removed periodically and moved to -70°C to ensure that no further changes in porosity will occur. The porosity and oil uptake are listed in Table 12.

Table 12 - Effect of initial porosity on oil uptake of a restructured potato product.

Porosity u_R

0.089 0.26

0.125 0.34

0.154 0.38

0.168 0.41

The data of Table 12 shows a linear relationship (R² =0.999) between porosity and oil uptake. These data emphasize the fact that the higher the initial porosity of the product, more oil is adsorbed by it.

Hence, it could be concluded bases on the data of Tables 11 and 12, that reducing initial porosity, as has been demonstrated by adding 3 % chick pea, reduces significantly oil uptake.

Example 11

Effect of Chick Pea Added to Flour Used for the Production of Breading

Chick peas were ground and sieved utillizing a 60-Mesh standard sieve. Chick peas (2 and 3%) were added to a 150-kg flour (used as the basic formula) replacing the respective amount of flour from the formula. The bread was commercially baked utilizing a standard fomula of 150 kg flour, yeast, salt, fat, sugar, and water. Salt content was 1 %, calculated on the basic formula. After proofing and baking for about 22 min at 220°C, the bread was cooled to ambient temperature, 23

cut to small pieces, air dried, ground and sieved through + 18, remaining on 60 mesh standard sieves. The bread crumbs were utilized as breading for the frying experiments.

Frozen poultry breasts, bought at a local supermarket, were thawed at room temperature, cut to pieces of 10 to 15 grams, were dipped for 30 sec into a commercial batter (utilized by the food industry to replace eggs). The meat samples were then placed on a screen allowing excess batter to drip off before it was transferred to a plastic bag containing the bread crumbs described above. The breaded meat samples were removed from the bag, excess breading was removed and the samples were fried. Frying conditions were: 180°C for 5 min. The meat samples were turned after 2.5 min from one side to the other in the fryer. The oil was treated as explained in Example 1. The control contained breaded meat samples with no chick pea and were prepared as described above. The results obtained (average of 5 replicates) are shown in Table 13.

Table 13 Effect of Chick Pea Added to Flour Used for the Production of Breading on Oil Uptake of Breaded Meat.

Breaded poultry breast

Control 2 % chick peas 3% chick peas

Oil uptake (%) 23.0 (± 1.1) 19.2 (±0.5) 18.6 (±0.4) u_R 0.72(±0.02) 0.63 (±0.02) 0.59 (±0.02)

The above data clearly show the reducing effect of chick peas added to the flour used for the baking of the breading. The reduction of oil uptake was 16.5 and 19.1 % at 2 and 3% chick peas in the breading, respectively.

Claims

Clai s

1. Food mixtures for producing fried food products comprising from 1 % to 10% by weight of ground legume together with from 0.2% to 1.5 % of GRAS salt, the balance being conventional food mixtures.

2. Food according to claim 1, wherein upon frying said the oil uptake is significantly reduced compared with the oil uptake of the conventional food mixture which form the balance in said mixture.

3. Food mixtures according to claims 1 and 2 wherein the interfacial tension of said food mixture is higher than the interfacial tension of the corresponding conventional food mixture.

4. Food mixtures according to claims 1 and 2 wherein the porosity of said food mixture is significantly reduced compared with the porosity of the corresponding conventional food mix.

5. Food mixtures according to claims 1 to 4 wherein the conventional food mixes comprises natural foods, reconstructed food products, engineered food, coatings, water, and/or mixtures thereof together with acceptable food additives.

6. Food mixtures according to claims 1 to 5 wherein the legume is selected from lentil and chick pea.

7. Food mixtures according to claims 1 to 6 wherein the legume constitute between 2% and 4% of the mixture.

8. Food mixture according to claim 6 wherein one of the food additives is alginate.

9. Food mixtures according to claims 1 to 7 wherein the GRAS salt is NaCl.

10. A method for obtaining fried food products with decreased oil uptake comprising:

a. covering said food with a coating selected from crumbs for breading and/or batter each comprising from 1 % to 10% of ground legume together with from 0.2% to 1.5 % of GRAS salt the balance being food ingridients used in known coatings, or alternatively,

b. adding to a conventional food mix an additive comprising a mixture of ground legume and GRAS salt, the content of said additive in the final mixture being from 1 % to 10% of ground legume and from 0.2% to 1.5% of said salt, and subsequently,

frying said food containing legume and salt by known frying methods.

11. Fried food products obtained according to the method of claim 10.

AMENDED CLAIMS

[received by the International Bureau on 07 December 1995 (07.12.95) ; original claims 2,4 and 5 amended; remaining claims unchanged ( 1 page) ]

1. Food mixtures for producing fried food products comprising from 1 % to 10% by weight of ground legume together with from 0.2% to 1.5% of GRAS salt, the balance being conventional food mixtures.

2. Food mixtures according to claim 1, wherein upon frying said food mixtures the oil uptake is significantly reduced compared with the oil uptake of the conventional food mixture which from die balance in said mixture.

4. Food mixtures according to claims 1 to 2 wherein the porosity of said food mixture is significantly reduced compared with the porosity of the corresponding conventional food mixture.

5. Food mixtures according to claims 1 to 4 wherein the conventional food mixtures comprises natural foods, reconstructed food products, engineered food, coatings, water, and/or mixtures thereof together with acceptable food additives.

8. Food mixture according to claims 6 wherein one of the food additives is alginate.