January 14, 2011
Do you have what it takes to be a food scientist? If you would like to find out, perform the following simple exercise, which was designed and executed by a team of professionals led by Fred Shih of the USDA’s Southern Regional Research Center. By the end, you will know (a) the difference between beer-battered fried foods and those fried in water-based batter, and (b) whether your future will be in the lab, gathering data that could improve the human condition, or at the bar, overfilling on unhealthy snacks.
1. Procure quantities of wheat flour, long-grain rice flour and pre-gelatinized rice flour. Also pick up some canola oil, Vidalia onions and tilapia filets. Oh, and beer.
2. Whip up six equal batches of batter: three with beer and each of the flours, and three with water and each of the flours. Be sure each batch achieves a viscosity of about 120 RVU. Then cut the filets into squares measuring 3.8 by 3.8 centimeters, and the onions into strips measuring 3.2 by 0.6 centimeters. Batter your fish and onions thoroughly, but save a sample of each batter by itself.
3. Fill your deep fryer with canola oil to a depth of 4.5 centimeters and heat the oil to 190 degrees Celsius. Fry everything—the beer-battered stuff for 2 minutes, the other stuff for 4. Also fry samples of each batter alone, until each one looks golden brown. Then let all your samples cool so we can begin our analysis.
4. First, we are going to determine how much oil each batter sample absorbed—”oil uptake,” in the lingo. Get out your supercritical fluid extraction system and fill the sample cartridge with this stuff in this order, starting from the exit end of the cartridge: 1 gram of Ottawa sand, 1 gram of diatomaceous earth and 1.5 to 3 grams of batter, to fill. Then use 65 mL of carbon dioxide to extract the sample at 51.71 MPa and 100 degrees C. For the love of Mike, set the restrictors to 140 degrees C, and keep the flow rate between 2.5 and 2.7 mL per minute. Pretty soon oil will be extracted from the batter sample. Weigh the oil and do some pretty complicated math, and you will have your oil-uptake data.
5. Now we can test for textural qualities, which eaters are more interested in anyway. Remember those batter-only samples from step 4? Take your Stevens QTS Texture Analyzer and, using an acrylic cylinder probe, perform a double bite test on them at 60 mm per minute until you reach an 80 percent deformation target. Your Texture Pro software will generate data on the hardness of each sample and the quantity of fractures. For the sake of simplicity, we will define “hardness” as the peak compression force attained during the first cycle of the force deformation curve, and “quantity of fractures” as the number of occasions the load decreased by 5 percent before reaching the target value in cycle 1. Okay?
6. And finally, we come to the all-important sensory evaluation—the moment when our carefully fried foods meet the tongue. Convene a panel of eight specialists trained in Sensory Evaluation Techniques (Meilgaard, et al., 4th edition) and feed them each four strips of coated fish or onion samples so they can evaluate them for hardness, fracturability, crispness and toothpacking. Just so everyone’s on the same page, let’s say “hardness” is the force required to compress the food; go with a scale of 1 to 14.5, with Philadelphia cream cheese being 1 and a Life Saver being 14.5. “Fracturability” is the force with which the sample breaks, with 1 being the force required to break a Jiffy corn muffin and 10 the force required to break a Finn crisp rye wafer. Now, “crispness” is the force and noise with which a sample breaks, on a scale of 3 (a Quaker low-fat chewy chunk granola bar) to 17 (Melba toast). “Toothpacking,” of course, refers to the degree with which the sample sticks to the teeth, from 1 (uncooked and unpeeled carrots) to 15 (Jujubes). After your panelists have tested the samples, record their scores on a computerized ballot-counting system that will tabulate and graph the scores for you.
Following these simple steps, the Shih team found that the oil uptake of beer batters was 9 to 18 percent greater than water-based batters. Its instrumental textural analysis found that beer batters fried up softer and more fracturable than water-based batters. And its panel of trained sensory evaluators found that beer batter made the tilapia filets and onion strips softer but crispier.
Your results may vary. But your method may not.
(Hat tip to NCBI ROFL.)
—by T. A. Frail
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