effect of starchy coating films on the reduction of fat

Paper

EFFECT OF STARCHY COATING FILMS ON THE REDUCTION OF FAT UPTAKE IN DEEP-FAT FRIED POTATO PELLET CHIPS MALAK M. ANGORa, RADWAN AJO a, WALID AL-ROUSANa and BASEM AL-ABDULLAHb* a Al-Huson University College, Al-Balqa Applied University, Al-Huson, Jordan b Department of Nutrition and Food Technology, Faculty of Agriculture, University of Jordan, Amman, Jordan *Corresponding author: [email protected]

Abstract The aim of this work was to investigate the influence of starch and bread crumbs as coating films at different levels (1, 2, 3, 4, and 5%) on fat reduction and product quality in deep fried potato pellet chips. The results obtained have shown that all coated samples increased fat reduction percent at all levels of starch and bread crumbs ranged from 12.89 to 44.37% and from 14.98 to 27.15%, respectively. The most effective level of starch was 4% for fat reduction, while the best level of bread crumbs was 3%. There were no significant (P > 0.05) differences between all samples in specific volume for fried potato pellet chips. The sensory attributes were improved as a result of using the coating materials at different levels and this is may be attributed to the reduction of fat absorption. - Keywords: coating films, deep fat frying, fat reduction, potato pellet chips -

Ital. J. Food Sci., vol. 25 - 2013

45

INTRODUCTION Deep fat frying plays an important role in food preparation, and it is one of the oldest cooking methods widely used to prepare tasty, distinctive flavor, aroma and crispy foods. It makes a unique contribution to sensory characteristics ( RIMAC-BRNČIĆ et al., 2004). Despite its considerable fat content and intensified consumer’s awareness of the relationships between food, nutrition and health, frying remains a principal cooking method (SAGUY and DANA, 2003). Some of the fried foods may contain up to 50% fat. For example, lipid content of French Fries increases from 0.2 to 14% and may reach 40% in fried potato chips (PINTHUS et al., 1993; AKDENIZ et al., 2006). Thus, fried foods have become a health concern. High consumption of lipids has been related to obesity and other diseases like coronary heart diseases. Furthermore, lipid oxidation during frying generates different oxidation byproducts, some of which are also associated with many diseases such as premature aging, membrane damage, heart disease and cancer (FALGUERA et al., 2011). Fried foods contribute a significant proportion of the total fat consumed in the world. Yet, aside from their high caloric value, fried foods can be nutritious and favorably compared with other cooking methods such as baking and boiling (PEDRESCHI and MOYANO, 2005). Properties of fried food surfaces are significant in influencing fat absorption. Application of coating is therefore a promising route to reduce oil content (NGADI et al., 2007). Coatings are reported to form barriers to moisture loss and subsequently fat uptake during frying. Deep fat frying involves the transfer of heat from the surrounding oil to the food interior together with the transfer of oil to the food and the transfer of water in the form of vapor from the food to the oil (SALVADOR et al., 2008). It has been well documented that edible coatings applied to food before frying aid in limiting moisture and oil transfer during frying (ALBERT and MITTAL, 2002). The surface modification by the hydrocolloid coatings can contribute to the reduction of the oil uptake during frying (KIM, 2011). Various surface coating materials such as isolated whey protein, powdered bread crumbs, starch, carrageenan, and their combinations were used to reduce moisture loss and fat uptake of chicken meat balls during deep fat frying ( AL-ABDULLAH et al., 2011). However, there is little published information about the use of starch and bread crumbs as coating materials to reduce moisture loss and fat uptake of potato pellet chips during deepfat frying. Therefore, the aims of this study are to study the effect of different percentages of starch and bread crumbs as coating mate-

46


rial films for potato pellet chips during deepfat frying on the level of fat reduction, and to study some important chemical, physical and sensory properties. MATERIALS AND METHODS Materials Potato pellet chips were purchased from a local market (JOPELLETS, Amman, Jordan). The coating materials used were commercial cornstarch (packed by Al- Tahuona Al- Fakhera Est. Amman) and bread crumbs that were prepared from pan bread by removing the crust of the pan bread (bread crumbs), then dried at 40ºC in an air oven (Memmert, 854 Schwapach, West Germany) for 8 hours. After that the dried bread crumbs was ground by using a mixer (Type 241, Moulinex, France), and then the ground crumbs were sieved to 150 µm particle size using a sieve (Type ASTME 1170, Mauer, Germany) and were placed in a glass jar until use. Coating solution preparation Coating solutions were prepared. For each coating material, five solutions of 1, 2, 3, 4, and 5% w/v were prepared. Each solution was heated to 90ºC for 5 minutes then cooled to room temperature. After that glycerol was added at a level of 3% w/v to these solutions as plasticizer. Potato pellet chips were dipped for 10 seconds in the coating solutions followed by air drying using an air blower; the dipping and drying procedures were repeated again to ensure uniform coating of the film on the products. Potato pellet chips without coating were used as control. The coated and uncoated samples were fried in an electrical deep-fat fryer (Emjoi power, Model UEDL- 206, China) filled with corn oil (Yara oil, Kafak Trading Company, Jordan) at 180° ± 2°C for 10 seconds (controlled temperature and time) during which a golden color surface was observed and the temperature of frying oil monitored by a digital thermocouple (K- type, APPA51, Taiwan). The oil was replaced after four frying batches. In each batch, twenty potato pellet chips were placed inside the frying basket. Frying was carried out by immersing the basket in the oil. After frying, samples were put on absorbing tissue paper for 5 minutes prior to testing. This was done to minimize the absorption of oil due to the cooling down period (SOUTHERN, 2000). The fried samples were left to cool down to ambient conditions for 1 hour. One part of the freshly fried samples was taken immediately for sensory evaluation, while the other parts were placed in plastic bags until chemical and physical analysis.

Samples analysis: Chemical methods Samples were analysed for moisture and fat content according to Association Official Analytical Chemists (AOAC) 2000 and each analysis was carried out in duplicate. Moisture content (MC) was determined by an oven-drying method in which potato pellet chips samples were placed in dishes and held in an oven (Memmert, 854, Schwapach, Germany) at 105°C until constant weight was reached. Fat content (FC) was determined by the Soxhlet method, which involve continuous vaporisation and condensation of petroleum ether during passage through a 5 g, moisture-free sample placed in the extraction thimble and covered with cotton wool. After 16 h, the extract was collected and subjected to distillation in order to collect the crude fat, which was then dried and weighed. The fat reduction capabilities of the edible coating in relative to control (uncoated samples) were estimated as the percent of fat content differences between uncoated and coated samples. Acidity percent (as oleic acid) and peroxide value were analyzed for frying oil at each frying batch according to AOAC (2000). The acidity and peroxide value for the frying oil were ranged from 0.22 to 0.25 and 9.9 to 9.96, respectively. Physical methods The volume of each sample was determined by immersion in a graduated cylinder filled with paraffin oil. Sample specific volume was calculated by dividing the sample weight by the volume of paraffin oil displaced (AKDENZ et al., 2006). Samples from each treatment were evaluated for sensory evaluation by an 11-member trained panel, chosen from the employees and students of the Department of Nutrition and Food Technology, Al-Balqa University. The panellists were of both sexes and different ages (18-50 years). Before evaluating the samples, they were familiarised with the test procedure and use of the scoring system. Each sample was evaluated for general appearance, colour, flavor, taste, crispiness and overall acceptability, using a descriptive ninepoint hedonic scale on which 9 was ‘like extremely’ and 1 was ‘dislike extremely’. Small amounts of bread and water were used between samples to neutralise any lingering taste from the previous sample. All treatments were evaluated in duplicate on separate occasions. Statistical analysis Statistical analysis of data was carried out using Statistical Analysis System package (SAS

Inc., 1997). The data obtained were analyzed using a Completely Randomized Design (CRD) to study the effect of treatments on the fat%, moisture%, specific volume, and sensory scores. The significant difference of the mean was determined using Least Significant Difference (LSD) method. RESULTS AND DISCUSSION Table 1 shows the fat and moisture content of the deep fried potato pellet chips coated with different levels of starch. The data shows that all levels of starch coating films used were effective in reducing the fat percent when compared to those of the uncoated one (control). However, the level of 4% of starch coating film sample had significantly (P ≤ 0.01) the lowest fat 22.23%, and the level of 1% starch coating film sample had significantly (P ≤ 0.01) the highest fat content 34.80% when compared with other coated samples, while the fat percent for uncoated sample (control) had 39.95 % fat. The moisture percent of different levels of starch as coating films for deep fried potato pellet chips ranged from 0.82 to 2.2% for all samples. The lower fat content of these samples was associated with higher moisture content. This result was as expected, since oil absorption occurs as moisture is removed from food during the frying process. The finding results confirmed by (SALVADOR et al., 2008; GARCÍA et al., 2004). The results of the analysis of fat and moisture content of the coated samples of potato pellet chips with different levels of bread crumbs and uncoated samples after deep-frying, are shown in Table 2. The data shows that the uncoated potato pellet chips sample had significantly (P ≤ 0.01) higher fat content 39.95% than those of the coated samples. Among the coated potato pellet chips samples, the sample coated with 3% bread

Table 1 - Fat and moisture content of the deep fried potato pellets chips at different levels of starch as coating films.

Treatments1 Starch %

Fat %

1% 2% 3% 4% 5% control

34.80b 1.00bc 31.55c 1.34b 26.42d 2.02a 22.23e 2.20a 26.00d 2.04a 39.95a 0.82c

P2

Moisture %

** **

Values are the means of two replicates, means with different matching letters within the same column are significantly (*; p ≤ 0.05, **; p ≤ 0.01) different according to LSD. 2 *; p ≤ 0.05, **; p ≤ 0.01. 1


47

crumbs had significantly (P ≤ 0.01) the lowest fat content 29.11% while that sample coated with 5% bread crumbs had the highest fat 33.97%. These results agreed with (Al-ABDULLAH et al., 2011). They found that the level of 3% of bread crumbs as coating films for chicken meat balls during deep-frying reduced fat uptake significantly when compared with the uncoated one (control). The moisture percent of the product at different levels of bread crumbs as coating films for deep fried potato pellet chips ranged from 0.82 to 2.49 for all samples. Fat reduction percent of control and coated samples with different levels of starch and bread crumbs as coating films for the deep fried potato pellet chips was shown in Fig. 1 and Fig. 2, respectively. All samples coated showed fat reduction at different levels of starch and bread crumbs. These levels ranged from 12.89 to 44.37% and from 14.98 to 27.15%, respectively. The most effective level of starch for fat reduction was at 4%. While the best level of bread crumbs was at 3%. These results were confirmed by (Al-

ABDULLAH et al., 2011) who concluded that using starch as coating films for minced chicken meat balls reduced fat uptake. Also agreed with (ALTUNAKAR et al., 2006; AKDENIZ et al., 2006), who concluded that fried foods coated with batters containing hydroxypropyl methylcellulose, xanthan, or guar gum had reduced oil content. KIM et al. (2011) were also obtained that the use of hydrocolloid as coating films of potato strips reduced the oil content up to 41% compared to control. The specific volume for all samples coated (starch and bread crumbs) and uncoated ranged from 2.49 to 2.61 g/mL. There were no significant (P > 0.05) differences in specific volume of the fried potato pellet chips between all samples. This reflects that the coated films did not affect the specific volume of the treatments. These results confirmed by (Al-ABDULLAH et al., 2011). They reported that minced chicken meat balls coated with different coating films showed no significant differences among all treatments, indicating a lack of any coating effect, on the product specific volume. Sensorial characteristics of the fried potato pellet chips are attractive to the consumers. Mean hedonic scores for appearance, color, flavor, taste, crispness and overall acceptability of the fried potato pellet chips coated with different levels of starch and bread crumbs are presented in Table 3 and Table 4, respectively. With the exception of the uncoated treatment the overall acceptability ratings for all treatments showed no significant differences (P > 0.05) between them for all the samples coated with different levels of starch and bread crumbs. The coated samples with different levels of starch and bread crumbs enhanced the overall acceptability. These results agreed with (AL-ABDULLAH et al., 2011) they concluded that the starch coating films for minced chicken meat balls yielded the highest overall-acceptability rating. Also (KILINCCEKER et al., 2009) concluded that the sen-

Fig. 1 - Fat reduction of deep fried potato pellet chips coated with different levels of starch.

Fig. 2 - Fat reduction of deep fried potato pellet chips coated with different levels of bread crumb.

Table 2 - Fat and moisture content of the deep fried potato pellets chips at different levels of bread crumb as coating films.

Treatments1 (Bread crump)

Fat %

1% 2% 3% 4% 5% control

32.98b 1.29c 33.08b 1.54c 29.11c 2.09b 32.92b 2.18b 33.97b 2.49a 39.95a 0.82d

P2

Moisture %

** **

Values are the means of two replicates, means with different matching letters within the same column are significantly (*; p ≤ 0.05, **; p ≤ 0.01) different according to LSD. 2 *; p ≤ 0.05, **; p ≤ 0.01. 1

48


Table 3 - Means of sensory evaluation scores of deep fried potato pellets chips coated with starch at different levels1.

Treatments

Appearance

Color

Flavor

Taste

Crispy

Overall acceptability

1% 7.70 7.80 7.40 7.30 7.40 2% 7.20 7.60 7.40 7.30 7.40 3% 7.30 7.40 7.60 7.40 7.50 4% 8.00 7.90 7.60 7.50 7.90 5% 7.00 7.40 7.85 7.70 8.00 control 7.00 7.00 6.70 6.50 6.70

7.80a 7.90a 7.90a 8.20a 8.50a 6.90b

P2 ns ns ns ns ns

**

Each mean is the average of 11 readings, where 9 refer to like extremely, 5 neither like or dislike and 1 refers to dislike extremely. Values within the same column followed by different letter are significantly (*; p ≤ 0.05, **; p ≤ 0.01) different according to LSD. 2 ns; p > 0.05, *; p ≤ 0.05, **; p ≤ 0.01. 1

Table 4 - Means of sensory evaluation scores of deep fried potato pellets chips coated with bread crumbs at different levels1.

Treatments

1% 2% 3% 4% 5% control P2

Appearance 7.70 7.30 8.10 8.00 7.20 7.10

Color

Flavor

Taste

Crispy

Overall acceptability

7.90 7.80ab 7.70a 7.70a 7.90a 7.80 8.00a 7.70a 7.80a 8.30a 7.60 8.1a 7.40a 8.00a 8.30a 8.00 7.4abc 7.40a 8.30a 8.30a 7.80 7.10bc 7.70a 8.10a 8.10a 7.40 6.70c 6.5b 6.70b 6.9b

ns ns ** *

**

**

Each means is the average of 11 readings, where 9 refers to like extremely, 5 neither like or dislike and 1 refers to dislike extremely. Values within the same column followed by different letter are significantly (*; p ≤ 0.05, **; p ≤ 0.01) different according to LSD. 2 ns; p > 0.05, *; p ≤ 0.05, **; p ≤ 0.01. 1

sorial features of the product were improved and that the sensorial properties of the coated fillets were more desirable than those of the uncoated fillets. While (MALLIKARJUNAN et al., 1997) reported that hydroxypropyl methylcellulose (HPMC) coatings improved the sensory attributes of the fried chicken nuggets than the uncoated samples. The other attributes (appearance, color, flavor, taste, and crispness) scores for all treatments of the fried potato pellet chips coated with different levels of starch and bread crumbs were found between the ranges of “like” very much to “like slightly”, included the uncoated (control) sample. There were no significant (P > 0.05) differences between different levels of starch coating samples for these attributes. Also bread crumb coating samples and control had no significant (P > 0.05) differences between different levels for only appearance and color, While these samples had significant differences for flavor, taste and crispy. The differences rating between all the treatments for all attributes were small, but significant in some cases. These results agreed with (AL-ABDULLAH et al., 2011) who obtained that minced chicken meat ball samples were coated with starch, bread crumb films and non-coated

acceptable by the sensory panel and any differences in sensory rating between products were generally small. Also these results were supported by (SALVADOR et al., 2008), who concluded that the differences between the coated and uncoated samples were generally small but significant in some cases. In any case, all attributes were acceptable to the sensory panels. CONCLUSION Using starch and bread crumbs as edible coating film for potato pellet chips prior deep fat-frying at different levels 1, 2, 3, 4, and 5% reduced fat absorption. The starch and bread crumbs coating at 4 and 3% levels were the most effective levels for fat reduction 44.27 and 27.15%, respectively. The coating films of starch and bread crumbs did not affects the specific volume of the potato pellet chips. Regarding, the sensory evaluation of the fried potato pellet chips, the sensory attributes were improved as a result of using the coating materials at different levels and this is may be due to the reduction of fat absorption.


49

ACKNOWLEDGEMENTS The authors acknowledge the funding support given by Al Balq’a Applied University/Jordan.

REFERENCES Akdeniz N., Sahin S. and Sumnu G. (2006). Functionality of batters containing different gums for deep-fat frying of carrot slices. Journal of Food Engineering, 75, 522-526. Al-Abdullah B., Angor M., Al-Ismail K. and Ajo, R. (2011). Reducing fat uptake during deep-frying of minced chicken meat-balls by coating them with some hydrocolloids materials. Italian Journal of Food Science, 23, 331-337. Albert S. and Mittal G. (2002). Comparative evaluation of edible coating to reduce fat uptake in a deep-fried cereal product. Food Research International, 35, 445-458. Altunakar B., Serpil S. and Gulum S. (2006). Effects of hydrocolloids on apparent viscosity of batters and quality of chicken nuggets. Chemical Engineering Communications, 193, 675-682. AOAC (2000). Official Methods of Analysis, 17th Edn. Washington, DC: Association of Official Analytical Chemists. Falguera V., Quintero J., Jiménez A., Muñoz J. and Ibarz A. (2011). Edible films and coatings: Structures, active functions and trends in their use. Trends in Food Science & Technology, 22, 292-303. García M.A., Ferrero C., Campana A., Bertola N., Martino M. and Zaritzky N. (2004). Methylcellulose coatings applied

to reduce oil uptake in fried products. Food Science and Technology International, 10, 339-346. Kim D., Lim J., Bae I., Lee H. and Lee S. (2011). Effect of hydrocolloid coatings on the heat transfer and oil uptake during frying of potato strips. Journal of Food Engineering, 102, 317-320 Ngadi M., Li Y. and Oluka S. (2007). Quality changes in chicken nuggets fried in oils with different degrees of hydrogenation. LWT- Food Science and Technology, 40, 1784-1791. Pedreschi F. and Moyano P. (2005). Oil uptake and texture development in fried potato slices. Journal of Food Engineering, 70, 557-563. Pinthus E.J., Weinberg P. and Saguy I.S. (1993). Criterion for oil uptake during deep-fat frying. Journal of Food Science, 58, 204-222. Rimac-Brnčić S., Lelas V., Rade D. and Šimundić B. (2004). Decreasing of oil absorption in potato strips during deep fat frying. Journal of Food Engineering, 64, 237-241. Saguy I.S. and Dana D. (2003). Integrated approach to deep fat frying: engineering, nutrition, health and consumer aspects. Journal of Food Engineering, 56, 143-152. Salvador A., Sanz T. and Fiszman S. (2008). Performance of methyl cellulose in coating batters of fried products. Food Hydrocolloids, 22, 1062-1067. SAS Institute. (1997). SAS Users Guide in Statistics, 7th Edn. SAS Institute, Inc.; Cary, NC. USA. Usawakesmanee W., Chinnan M., Wuttijumnong P., Jangchud A. and Raksakulthai N. (2008). Effect of edible coating ingredients incorporated into predusting mix on moisture content, fat content and consumer acceptability of fried breaded product. Songklanakarin Journal of Science and Technol., 30 (Suppl.1), 25-34.

Paper received March 12, 2012 Accepted July 20, 2012

50
