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FATS AND OILS: MELTINGPOINTS, PLASTICITY, EVALUATIONS, EFFECTS OF COOKING TEMPERATURES AND TIMES, AND COATING SYSTEMS
Sarah Hill Nutrition 2200 Lab W 5-8 October 22, 2014
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PURPOSE The purpose of this lab was to learn and understand the content and properties of different
available fats. The fats were evaluated for the plasticity, melting point and composition, effects of cooking temperature and time, and the effects of different coatings for cooking had o n the absorption of fats. After the tests, the fried products were evaluated with different available coating systems.
METHODOLOGY For the melting point and composition comp osition of solid fats, the student had to pack the assigned fat into
a 1/3-cup metal measuring cup and level it off with a rubber spatula. Then, the student transferred it to a 1-cup metal measuring up and an d placed it in a frying pan and placing the frying pan on the range without, without the range on. Next, water was poured into the pan around the metal cup without getting any water on the fat. After the water, the student turned on the range and began to heat the fat slowly and took the initial temperature when the edge of the fat began to melt. The student continued to heat the fat and recorded the th e temperature at which all the fat was melted. Once the fat was completely completel y melted, the student transferred the fat from the metal cup to a 100 milliliter graduated cylinder and recorded the volume. The graduated cylinder then was set aside to cool and recorded any notable temperatures and layering that occurred and the volume of the layers. The final temperature was recorded when the fat lost its ability to flow freely. Lastly, the appearance of the solid fat was recorded (Brannan).
In the plasticity of fats experiment, the student packed a 1/3 measuring cup with the th e assigned fat and leveled it off with a rubber rub ber spatula. The student had to make sure that the fat was at room temperature. Then, the student used a penetrometer and tested the penetration of the fat; recorded the penetration and the temperature. Next, the student smoothed the fat and placed it in the
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refrigerator for an hour. After the hour, the student then retested the penetration using the penetrometer; recorded the penetration and the temperature. Again, the student smoothed the fat and placed it in the freezer freez er for an hour. Then retested the penetration; recorded the final penetration and temperature (Brannan).
In the evaluation of different types of fat, the student had to taste each fat for the flavor, appearance, spreadability, and other. Then, recorded the results (Brannan).
In the effects of cooking temperature on fat ab sorption, the cut 2 biscuits into 8 equal e qual pieces, weighed and recorded the weight of each pair of biscuits. With the deep fat fryer around 225 degrees Fahrenheit, the temperature was recorded. The student then fried group one of the biscuits for one and a half minutes, 45 seconds on each side and drained on a paper towel. The weight was recorded along with weight gain; percent weight gain, doneness, appearance, and oiliness. Then the fryer’s temperature was increased to 275 de grees Fahrenheit, the temperature was recorded. Group two was then fried for a minute and a half, 45 seconds on each side and drained on a paper towel. The results were recorded (same as above). The fryer’s temperature was increased to 325 degrees Fahrenheit, temperature recorded. Group three was fried for a minute and a half, 45 seconds on each side, drained on a paper towel. The results were recorded (same as above). The fryer’s temperature was increased to 375 degrees Fahrenheit, temperature recorded. The last group was fried for a minute and a half, 45 seconds on each side, drained on a paper towel. The results were recorded (same as above). Each group was reweighed in order to calculate the weight gain or loss and the percentage of weight gain or loss. All weights were recorded in grams (Brannan).
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In the effects of cooking time on fat absorption, the student had to cut 2 biscuits into 8 equal pieces and recorded the weight of each pair. The student made sure that the fryer was at 375 degrees Fahrenheit before frying. Group one was fried for 30 seconds, 15 seconds on o n each side and evaluated for weight gain, percentage of weight gain, doneness, appearance, and oiliness. Group two was fried for one minute, 30 seconds on each side, results recorded (same as above). Group three was fried for a minute and a half, 45 seconds on each side; results were recorded (same as above). Group four was fried for two mi nutes, a minute on each side; results were recorded (same as above). Each pair was reweighed and recorded to calculate the weight gain or loss and percentage weight gain or loss. All weigh ts were recorded in grams (Brannan).
In the evaluation of different coating systems, the students were directed to follow the instructions on their assigned coating packages. The chicken was then fried until internal temperature reached 160 degrees Fahrenheit (Brannan).
RESULTS In the melting point and composition of o f solid fats, the fat for shortening was Crisco all-
vegetable shortening. It had a serving size of 1 tablespoon, 110 calories per serving, 3 grams of saturated fat, 0 grams of trans fat, 6 grams of po lyunsaturated fat, and 2.5 grams of monounsaturated fat. The shortening had an initial temperature of 78 degrees Fahrenheit, final temperature of 155.5 degrees Fahrenheit, and a range of 77.5 degrees Fahrenheit. It had a total volume of 66 ml with 0 ml of water; it solidified at 72.5 degrees Fahrenh eit. For the margarine, Kroger brand was used. It had a serving size of 1 tablespoon with 100 calories per serving. It contained 3.5 grams of saturated fat, 0 grams of trans fat, 3.5 grams of polyunsaturated fat, and 4
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grams of monounsaturated fat. It had an initial temperature of 88 degrees Fahrenheit, final temperature of 138 degrees Fahrenheit, and a range of 50 degrees Fahrenheit. The total volume was 64.5 ml with 0 ml of water recorded and solidified at 74 degrees Fahrenheit. Country Crock had a serving size of 1 tablespoon with 70 calories per serving. It contained 2 grams of saturated fat, 4 grams of polyunsaturated fat, and 1.5 grams of monounsaturated fat. The initial temperature was 85 degrees Fahrenheit; final temperature was 148 degrees Fahrenheit, and a range of 63 degrees Fahrenheit. Its total volume was 66 ml with 26 ml of water, and solidified at 73 degrees Fahrenheit. Palm oil o il had a serving size of 1 tablespoon with 120 calories were serving. It contained 6.7 grams of saturated fat, 1. 3 grams of polyunsaturated fat, and 5 grams of monounsaturated fat (Sparkpeople). The palm oil had an initial temperature of 75.5 degrees de grees Fahrenheit, a final temperature of 165.5 degrees Fahrenheit, and a range of 91 degrees Fahrenheit. Its volume was 62 ml with 0 ml of water and solidified at 78 degrees de grees Fahrenheit. Blue Bonnet had a serving size of 1 tablespoon with 70 calories per serving. It contained 1.5 grams of saturated fat, 1.5 grams of trans fat, 2.5 grams of polyunsaturated fat, and 2 grams of monounsaturated fat (Blue Bonnet). Its initial temperature was 80 de grees Fahrenheit, a final temperature of 116 degrees Fahrenheit, and a range of 36 degrees Fahrenheit. The total volume was 76 ml and contained 26 ml of water; it solidified at 74 degrees Fahrenheit. The vegetable spread had a serving size of o f 1 tablespoon with 50 calories per serving. It contained 1.5 grams of saturated fat, 0 grams of trans fat, and a total of 5 grams of fat. Its initial temperature was 75 degrees, a final temperature at 112 degrees Fahrenheit, and a range of 37 degrees Fahrenheit. It had a total volume of 60 ml with 34 ml of water; it solidified at 74 degrees Fahrenheit. The butter was Kroger unsalted butter, it had a serving size of 1 tablespoon with 100 calories per serving. It contained 7 grams of saturated fat, 0 grams of trans fat, and a total of 11 grams of fat. Its initial
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temperature was 87 degrees Fahrenheit, a final temperature of 165 degrees Fahrenheit, and a range of 78 degrees Fahrenheit. Its total volume was 77 ml with 4 ml of water; it solidified at 73 degrees Fahrenheit. The lard was Armour lard and hydrogenated lard. It had a serving size of 1 tablespoon with 120 calories per serving. It contained 6 grams of saturated fat, 0 grams of trans fat, and a total of 13 grams of fat. It had an initial temperature of 7 6 degrees Fahrenheit, a final temperature of 147.5 degrees, and a range of 71.5 degrees Fahrenheit. It had a total volume 67 ml with no water recorded; it solidified at 78 degrees Fahrenheit (Culley). All values are presented below in Tables 1 and 2.
Table 1: Type of fat with melting points, volumes, and temperature of solidification. Type of Fat Shortening Margarine Country Crock Palm Oil Blue Bonnet Vegetable Spread Butter Lard
Melting Point (F) Initial Final Range 78 155.5 77.5 88 138 50
Volume (ml) Total Water 66 0 64.5 0
Solidification Temperature (F)
85 75.5 80
148 63 165.5 91 116 36
66 62 76
26 0 26
73 78 74
75 76 76
112 37 165 78 147.5 71.5
60 77 67
34 4 0
74 73 78
72.5 74
Table 2: Nutrition Facts for the fats. Type of Fat Serving Size Calories Saturated(g) Trans(g) P. Unsat.(g) M. Unsat.(g) Shortening 1 Tbsp. 110 3 0 6 2.5 Margarine 1 Tbsp. 100 3.5 0 3.5 4 Country Crock 1 Tbsp. 70 2 0 4 1.5 Palm Oil 1 Tbsp. 120 6.7 0 1.3 5 Blue Bonnet 1 Tbsp. 70 1.5 1.5 2.5 2 Vegetable Spread 1 Tbsp. 50 1.5 0 -* -* Butter 1 Tbsp. 100 7 0 -* -* Lard 1 Tbsp. 120 6 0 -* -* *not given on the nutrition facts panel. P. – P. – polyunsaturated; polyunsaturated; M.- monounsaturated
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In the plasticity of fats experiment, the same fats as above were tested at different temperatures for penetration (mm), using a penetrometer, and te mperatures at which the penetration occurred. Shortening at room temperature was 75.5 degrees Fahrenheit and a penetration on 18.9 mm. Refrigerator temperature was 55.5 degrees Fahrenheit and a penetration of 17.5 mm. Frozen temperature was 27.5 degrees Fahrenheit and a penetration of 13.4 mm. For margarine, room temperature was 70.5 degrees Fahrenheit and a penetration of 16.0 mm. Refrigerator temperature was 56.5 degrees Fahrenheit and a penetration of 13.3 mm. Frozen temperature was 26.5 degrees Fahrenheit and a penetration of 5.3 mm. Country Crock at room temperature was 71.5 degrees Fahrenheit and a penetration of 18.1 mm. Refrigerator temperature was 56 degrees Fahrenheit and a penetration of 34.1 mm. Frozen temperature was 24.5 degrees Fahrenheit and a penetration of 12.3 mm. Palm oil had a penetration of 19.9 mm at room temperature of 72.5 degrees Fahrenheit. Refrigerator temperature was 57.5 degrees Fahrenheit and a penetration of 11.6 mm. Frozen temperature was 37.5 degrees with a penetration of 22.5 mm. Blue Bonnet had a room temperature of 63 with a penetration of 10.2 10. 2 mm. Refrigerator temperature was 60 degrees Fahrenheit with a penetration of 8.5 mm. Frozen temperature was 34 degrees Fahrenheit with a penetration of 18.4 mm. Vegetable Spread had a room temperature of 70 degrees Fahrenheit and a penetration of 26.5 mm. Refrigerator temperature was 63.5 degrees Fahrenheit with a penetration of 20.6 mm. Frozen temperature was 15 degrees Fahrenheit with a penetration of 3.0 mm. Butter had a room temperature of 71 degrees Fahrenheit with a penetration of 11.5 1 1.5 mm. Refrigerator temperature was 47 degrees Fahrenheit with a penetration of 2.2 mm. Frozen temperature was 13 degrees Fahrenheit with a penetration of 1.3 mm. Lard had h ad room temperature of 72 degrees Fahrenheit with a penetration of 11.1 mm. Refrigerator temperature was 36.5 degrees Fahrenheit with a penetration of 4.5 mm. Frozen temperature was 7.5 degrees Fahrenheit
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with a penetration of 1.0 mm (Culley). Table 3 shows the values of each fat at room temperature, refrigerated temperature and frozen temperature.
Table 3: Fats penetration values at room, refrigerated, and frozen temperatures. Room Temperature Refrigerator Temperature Frozen Temperature Type of Fat Penetration Fat Temp Penetration Fat Temp Penetration Fat Temp (mm) (F) (mm) (F) (mm) (F) Shortening 18.9 75.5 17.5 55.5 13.4 27.5 Margarine 16.0 70.5 13.3 56.5 5.3 26.5 Country Crock 18.1 71.5 34.1 56 12.3 24.5 Palm Oil 19.9 72.5 11.6 57.5 22.5 37.5 Blue Bonnet 10.2 63 8.5 60 18.4 34 Vegetable Spread 26.5 70 20.6 63.5 3.0 15 Butter 11.5 71 2.2 47 1.3 13 Lard 11.1 72 4.5 36.5 1.0 7.5
For the evaluation of different types of fats, the students had to try each fat and describe the appearance, aroma, spreadability, mouthfeel, and flavor. Since each student did this, the results were subjective. The students had to choose 8 different fats and then recorded the results. For the shortening, it was solid, white, thick, and cream y. It had a smell of cooked vegetables and buttery. It was easily spread at room temperature. It had a smooth and creamy texture and did not taste like anything besides oil. Margarine was a light yellow color, very soft at room temperature and creamy. It smelled like old oil that was starting to go rancid. It was very easily spread. It melted very quickly, was soft, and had a creamy texture that left oil residue in the mouth. This also did not have a strong taste of anything. The Earth Balance organic coconut spread was off white and very soft. It smelled just like coconuts. It was easily spread at room temperature and had an oily layer. It melted quickly and had a soft, creamy texture that tasted like coconut. Olivio original spread had a light yellow color that smelled like olives. It spread easily and melted
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quickly with a creamy texture. It did not taste like anything at first, but it had a salty aftertaste. Country Crock was light yellow in color, it smelled like vegetable oil but sweeter. It spread easily and melted quickly with a salty salt y taste. Smart Balance was yellow with a shiny, oil la yer on top. It smelled like butter but sharper and more d istinct. It spread moderately with a smooth, creamy texture and a salty taste. Yogurt Y ogurt butter was light yellow without any oily layer. It had a faint plain yogurt smell and did not spread easily. It had a dense, but smooth texture and was really salty. Vegetable spread was deep yellow with a shiny, oily layer and had h ad a strong vegetable, buttery smell. It spread easily and had a sticky texture. It did not taste like much besides oil and had no aftertaste.
For the effects of cooking temperature on fat absorption, the student had to deep fry biscuit dough at varying temperatures for one and a half minutes. The initial weight, weight after frying, weight gain/ loss, percent weight gain, donen ess, appearance, and oiliness were recorded for each pair of dough balls. Group one was fried at 225 degrees Fahrenheit and had an initial weight of 7 grams. After frying, its weight was recorded at 5 grams; it had a weight loss of 2 grams with no percentage of weight gain. The dough balls were hardly cooked, had a very light golden crust, that was slightly oily, and the dough was still semi- raw in the center. The fryer’s temperature was increased to 275 degrees Fahrenheit. Group two had an initial weight of 7 grams and after frying the weight remained the same; leading to 0 grams of weight gain and 0 percent weight w eight gain. It had a medium golden brown crust, light, fluffy center, and w as a little oilier than group one. The temperature of the fryer was increased to 325 degrees Fahrenheit. Group three had an initial weight of 4 grams and after frying weighed 5 grams. It had a weight gain of 1 gram and 25 25 percent weight gain. The crust was a dark golden brown and hard and the center was denser then
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the previous group with more oil as well. The fryer was increased to 375 d egrees Fahrenheit. Group four had an initial weight of 3 grams and after frying weighed 5 grams. It had a weight gain of 2 grams and 67 percent weight gain. Its crust was medium brown and hard, and the center was very dense with a lot more oil then the previous group. Table 4 gives the values of weight wei ght before and after frying.
Table 4: Weight values before and after frying at various temperatures. Temp (F) Initial Wt. (g) After Wt. (g) Wt. Gain (g) 225 7 5 -2 275 7 7 0 325 4 5 1 375 3 5 2
% Wt. Gain (g) 0 25 67
In the effects of cooking time on fat absorption, the student had to deep fry dough balls at varying time intervals at a temperature of 375 d egrees Fahrenheit. The initial weight, weight after frying, weight gain/ loss, percent weight gain; along with doneness, appearance, and oiliness were recorded for each group. Group one’s dough balls were fried for 30 seconds. The initial weight was 11 grams and after frying weighed 11 grams; there was no weight gain. It had a light golden brown crust with a soft flaky center and was very ver y oily. Group two was fried for 1 minute. It had an initial weight of 13 grams and after frying weighed 15 grams. It had a weight gain of 2 grams and a percentage weight gain of 15 percent. It had a dark golden brown crust with a soft white inside and was also very v ery oily. Group three was fried for 1.5 minutes. It had an initial weight of 8 grams and after frying weighed 12 grams. It had a weight gain of 4 grams and a percentage weight gain of 50 percent. It had a dark brown crust with a dense center and was very oily. Group four was fried for 2 minutes. It had an initial weight of 12 grams and after frying weighed 9 grams. It had a weight loss of 3 grams and no percentage of weight gain. It had a very dark brown crust with a dense, soft yellow center and was very v ery oily. Table 5 shows the
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values of the initial weight, after weight, weight gain, and percentage of weight gain at the varying times.
Table 5: Weight values before and after frying at various time intervals. Time (min) Before Wt. (g) Wt. After (g) Wt. Gain (g) .5 11 11 1 13 15 2 1.5 8 12 4 2 12 9 -3
% Wt. Gain 15 50 -
In the evaluation of different coating systems, the student coated chicken with different coatings and deep-fried the chicken. The Th e students followed the instructions on their assigned coating and recorded the appearance, flavor, mouthfeel, and others. Panko breadcrumbs had a golden brown appearance with an oily, chicken flavor. The crust was crunchy, but the chicken was chewy and dry. Plain breadcrumbs had a dark brown crust with black spots. The crust had an oily, burnt taste and the chicken was chewy and oily. Batter had a medium golden brown crust with an oily, chicken flavor. The crust was crunchy and the chicken was oily and chewy. Breadcrumbs and batter had a dark brown with black spots crust. It tasted like burnt oily chicken. The crust was crunchy and the chicken was chewy and dry. Panko breadcrumbs and batter had a dark golden brown crust and tasted like oily chicken. The crust was crunchy and the chicken was oily and tender. Flour had a light golden brown color and tasted like oily chicken. The crust was softer and oily and the chicken was moist, tender, and oily. Seasoned flour had a medium brown color and tasted like oily chicken. Its crust was crunchy and the chicken was oily, moist, and tender. Frying Magic was brown in color and also tasted like oily chicken. Its crust was crunch y and the chicken was not as oily as a s the others, moist and tender.
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DISCUSSION The melting point and solidification of different fats are related to the composition of the fat.
Fatty acids are made up of fatty acids that contain glycerol, polyhydric alc ohol containing three carbon atoms, each of which is joined to a hydroxyl group (McWilliams). These fatty acids can be saturated, fatty acids containing all of the hydrogen atoms they can possibly hold; or unsaturated, either monounsaturated or polyunsaturated, fatty acids with one or two or more double bonds (McWilliams). Depending on how saturated or unsaturated the fatty acids are influences the fat’s melting point, the temperature at which the crystals of a solid fat melt; and the length of their chain (McWilliams). The longer the chain, the more solid the fat is at room temperature and the higher the melting point. Also influencing the melting point is the degree d egree of saturation. Fats that are more saturated have higher melting points. For example, stearic acid, a saturated, 18 carbon fatty acid, has a melting point of about 157 degrees Fahrenheit, while oleic acid, a monounsaturated acid with 18 carbons and one double bond has a melting point of about 57 degrees Fahrenheit; a polyunsaturated fatty acid, linoleic acid, with 18 carbons and two double bonds has a melting point of about 23 degrees Fahrenheit (McWilliams). Whether the fatty acid is cis, the hydrogens attached to the carbon atoms on either end of the double bond are from the same orientation and cause a lower melting point; or trans, the hydrogens attached to the carbon atoms on either end of the double bond are from opposite directions and cause a higher melting point (McWilliams). In this case, after melting the fats and letting them set, those fats that solidified almost completely were fats that were mostly made up of saturated fatty acids, while those fats that separated were mostly unsaturated fatty acids.
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The degree of penetrations is also related to the degree of saturation of the fats and the temperature the fats are cooled at to form the crystals. Most industries put the fats through a process of tempering, removing heat resulting from crystallization crystallization of fats and maintaining a selected temperature to promote the formation of stable, desirable cr ystals (McWilliams). (McWilliams). By altering the temperature of which the fats are stable, effects the crystal formation. As the crystal formations change, based on the temperature, the amount of force that’s needed to penetrate the fats is also altered. As the penetration levels decrease, it shows tha t more force is required to fully penetrate the fat, resulting in more lower pen etration levels at different temperatures. Fats that contained less water required more force to pe netrate the fats at decreasing temperatures due to the altered forms of the crystals, while fats that were more saturated needed less force.
When deep- frying foods it is best be st to keep the oil at a temperature of about 350 degrees Fahrenheit (McWilliams). The temperature of the oil and the food being cooked influences fat absorption. If the temperature is too low, it takes longer for the food to cook, resulting in more fat absorption. If the temperature is too high, the o uter part of the food will cook too quickly; and the inside is not fully cooked. With temperatures on the lower end, below 350 degrees Fahrenheit, the fat is more easily absorbed. Also d epending of the composition of the dough, more fat may be absorbed. If the dough contains a high amount of sugar and fat, more fat absorption will occur (McWilliams).
The cooking time will affect the amount of fat absorbed depending on the time interval and the temperature at which the food is being cooked. The longer it takes to cook the food more fat is absorb (Kikel). When the dough balls lost weight, it was most likely due to the loss lo ss of water.
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When the dough balls gained weight, it was due to the fat absorption because of the long exposure time to the oil (Kikel). To maintain the weight, it is best to cook the food at the optimal time and temperature; the fat absorbed replaces the water lost.
As for the type of coating system, s ystem, the composition of the system will affect the amount of fat that is absorbed. The coating systems that contained a high amount of fat and sugar will increase the amount of fat absorbed (McWilliams). The coating systems that used onl y breadcrumbs and flour resulted in a lower fat absorption because the y contained low amounts of fat and sugar before frying.
CONCLUSION When testing different fats’ melting points, the results were influenced by the de gree of
saturation and the overall composition of the fat. The more saturated the fat, the higher the melting point will be and the more solid it is at room temperature. Plasticity maybe affected depending on the formation of the crystal structures at different temperatures. With decreasing temperatures, the crystals are larger; this requires more force to be used in order to penetrate the fats. Also, the more saturated the fat, more force it required. Tasting different fats is subjective, so depending on the person who is trying the fat; it will all have a different flavor and aroma. When deep frying foods, the lower the temperature, the more fat that will be absorbed. Fat absorption is also influenced by the dough composition, more sugar and fat results in more fat absorption. With cooking time, the longer the d ough is exposed to the oil, the more fat will be absorbed. Cooking the dough until the inside is fully cooked is the optimal time. Depending on the type of coating system used will influence the fat absorption. Systems with high amounts of
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fat and sugar will absorb more fat and result in a greasier product. Overall, fat is influenced b y the degree of saturation and the fatty acid composition.
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REFERENCES Blue Bonnet. 2014. Nutrition Facts Panel. Brannan, R.G. 2013. Laboratory Manual for NUTR 2200. Pp. 67- 74. Culley, Amanda. 2014. Fats and Oils Data. PPT. Kikel, Alex. N/A. Effect of Cooking Time on Fat Absorption. McWilliams, Margaret. 2012. Foods: Experimental Perspectives ed. 7. Pp. 237-240, 273-274. SparkPeople. 2014. Calories in Palm Oil.
