Estimation of quality attributes and frying times of cottonseed and sunflower oil blend during deep-fat frying of potato chips [electronic resource].

Includes references.

The chemical. physical and some sensory changes induced upon deep-tat frying of potato chips in a blend of cottonseed nnd sunflower oil were investigated. The chemical changes were correlated with the frying times aiming at establishing prediction models for estimating frying times. The oil blend became dark in colour after each successive frying. The correlation coefficient between the frying time and A400 was very high (r=09967). Similar trend was also observed in the relationship between the trying times and A450• Oil viscosity increased significanrly with increasing frying times indicating evidence of thennal decomposition of flying oil blend. The correlation coefficient betwoon the frying times and the relT active index was high (r=0.9898). Slight and continuous losses in unsaturated fatty acids of the oil blend during deep.-fat frying of potato chips have taken place. The peroxide value (meq O:/kg oil) increased initially from 3.86 to 11.81 after 10 fl)lings, then dropped to 5.13 after 20 fryings followed by another rapid increase to 19.76 (mcq. O2/kg oil) after 30 fryings. The UV absorption at 232001 increa.<;ed initially from 0.4 to 1.5 after only 5 fryings and unchanged from the 5th frying to the 20lh frying then dropped after 30 fryings. A considerable increase in the TBA value has occurred up to the 20th frying and then the TBA value showed no change tor the next 10 fryings. The correlation coefficient between (he frying time and TBA value was 0.93. The rate of polar compounds formation for the first 5 tiyings was 3.62 mg/100mg oil/hr. whereas from the 51h Irying to the 30lh trying such rate was reduced to only 1.12 mg/100mg oillhr. Sensory evaluation ofthe oil blend indi· cated that odour ,md colour scores were inversely related to the ti)'ing time. The most imponant and accurat'c mathematical models which express the relationsbip between the independent and dependant variables were established. The frying thnc could be successfully and accurately predicted by wise and intelligent chose of dependant variables incorporated in the best fit equations. Keywords: qualify attributes, deep-fal frying, Cottonseed oil, sunflower oil, Potato chips

Summary in Arabic.