Julieta Rosete Hidalgo, María Elena Sosa Morales, Jorge F. Vélez Ruiz Superheated Steam as Pretreatment to Reduce Oil Uptake During Deep-Fat Frying of Chicken Nuggets Julieta Rosete Hidalgo, María Elena Sosa Morales, Jorge F. Vélez Ruiz Universidad de las Américas, Puebla, México Stefan Cenkowski University of Manitoba, Winnipeg, Canada CSBE/SCGAB, Vancouver, BC, Jul 13-16, 2008

Why? The current proportion of children in America who are overweight have tripled since 1980.   Approximately 65% of people are overweight.  The data also show that 31% of people now suffer from Obesity, compared with only 23% in 1994. According to American statistics, obesity increases a risk of a number of life threatening conditions, such as diabetes, heart disease, stroke, high blood pressure, and some types of cancer.

Overall objective To lower the oil uptake in deep-fat frying of chicken nuggets by pre-treating them with superheated steam prior to frying Specific objectives compare the final moisture content, oil uptake, and the quality attributes (color, texture, density, thermal conductivity)

Materials and Methods Frying of nuggets at 140 and 160°C, 3 min SS temperature: 110 and 140 ºC Duration of treatment: 3 y 5 min SS flow rate: 11.23 kg/h at 5 kPa

Methods Temperature: Thermocouples type J Moisture determination: 110°C, 24 h (AOAC, 1995) Oil content: petroleum-ether extraction 6 h, 78 min Thermal conductivity: Thermal properties analyzer (KY-2, Decagon Devices)

Methods Density: mass volume displacement method Texture: Penetration 15%, 5mm/s with a 2 mm dia. probe (Texture Analyzer TA- TX2) Color: Hunter Lab values at two locations (Chroma Meter CR-400 (Minolta) Statistical analysis: analysis of variance (ANOVA) and means separated using Tukey’s method at 0.05 significance level (Minitab)

Conditions used in combined SHS and deep-fat frying of chicken nuggets Variable Conditions Control 1 2 3 4 Steam temperature,°C - 110 140 SS treatment time (min) 5 Frying time,160°C (s) 180 100 60 70 50

Moisture loss during deep-fat frying of chicken nuggets at 160C

Oil gain during deep-fat frying of chicken nuggets at 160C

Temperature changes during deep-fat frying of chicken nuggets for a control sample …and for SS treatment with conditions 1- 4

The penetration force measured for chicken nuggets pretreated with SS and fried (conditions 1- 4) vs control Control 1 2 3 4

Density of fried and SS pre-treated nuggets as compared to control 1 2 3 4

Conclusions In comparison to 3-min deep-fat frying, a reduced oil uptake was obtained in the core (2.5% wb) and in the crust (16.7% wb) when SS treated at110C for 5 min followed by 1-min frying but resulted in higher moisture content of the core (1.7-3.7% wb) and the crust (13.5-18.8% wb). No change: in density, thermal conductivity Similar texture and more yellowish color