Impact of deep-fat-frying on some plantain micronutrients

Plantains and bananas are one of the major staple foods of sub-Saharan Africa and Latin-America. These fruit are source of dietary minerals and vitamins. Deep-fat frying unit operation is widely used for the transformation of plantain in Latin-America and in Africa. The aim of this research was to evaluate the influence of deep-fat frying on the micronutrients of plantain (Musa AAB "barraganete"). Influence of the raw material (two batches) was analyzed. Cylinders (diameter 30 mm, thickness 10 mm) of plantain were fried at four thermal treatments (120-180° C and from 24 to 4 min). Molecules of nutritional interest with water soluble properties (potassium, L-ascorbic acid) or lipid soluble properties (alpha-carotene, beta-carotene) were quantified during the course of frying. One plantain batch was initially rich in L-ascorbic acid (24.4 ± 0.9 mg/100mg) and poor in total carotenoid (0.6 ± 0.3 mg/100mg), while the other was poor in L-ascorbic acid (7.5 ± 0.3 mg/100mg) and rich in total carotenoid (2.1 ± 0,7 mg/100mg). On line measurements of the water content and internal temperature profile allow to characterize the behaviour of bath products during deep-fat frying. The thermal study used the cook value as indicators of the effect of thermal history on quality. Potassium was determinate by ICP; L-ascorbic acid and carotenoid determinations were performed by HPLC. Deep-fat frying had no significant effect on potassium contents at any frying- conditions. Exclusively with the plantain initially rich in L-ascorbic acid, a-carotene and ,alpha-carotene, significant losses were observed. The average loss on L-ascorbic acid. alpha-carotene and beta-carotene were close to 75%, 44% and 35%, respectively. Cook values were very different at any frying conditions, while the lasses of micronutrient were not significantly different at the four frying treatments. Cook value parameters does not seem relevant. These couldn't be explained just with a first order kinetic thermal degradation behaviour. Perhaps, the heterogeneous distribution of micronutrient across the plantain (in radial direction) and/or cellular scale could explain of such behaviours. However it's difficult to develop more extensive assumptions without histological information of the micronutrient localization in plantain. (Texte intégral

A comparative study of the characteristics of French Fries produced by deep fat frying and air frying

Air frying is being projected as an alternative to deep fat frying for producing snacks such as French Fries. In air frying, the raw potato sections are essentially heated in hot air containing fine oil droplets, which dehydrates the potato and attempts to impart the characteristics of traditionally produced French fries, but with a substantially lower level of fat absorbed in the product. The aim of this research is to compare: 1) the process dynamics of air frying with conventional deep fat frying under otherwise similar operating conditions, and 2) the products formed by the two processes in terms of color, texture, microstructure, calorimetric properties and sensory characteristics Although, air frying produced products with a substantially lower fat content but with similar moisture contents and color characteristics, it required much longer processing times, typically 21 minutes in relation to 9 minutes in the case of deep fat frying. The slower evolution of temperature also resulted in lower rates of moisture loss and color development reactions. DSC studies revealed that the extent of starch gelatinization was also lower in the case of air fried product. In addition, the two types of frying also resulted in products having significantly different texture and sensory characteristics

Fluorescence spectroscopy for analysing deterioration of palm olein in batch deep-fat frying

Palm olein has been commercially used as frying medium in batch deep-fat frying. During frying, the oil usually deteriorates due to the exposure to high temperature. In this study, a fluorescence spectroscopy technique was applied to monitor the deterioration of refined, bleached, and deodorized palm olein (RBDPO) in batch deep-fat frying. 22.5 kg of French fries were used as the frying material. In 30 batches, the french fries were intermittently fried at 185 ± 5°C for eight hours a day over five consecutive days capturing 40 hours. The fluorescence intensity of the RBDPO was recorded with excitation at 390 nm and resulting emission of 465 nm. The fluorescence intensity of the RBDPO over five days of frying decreased considering the wavelength range of emission 430-640 nm and excitation 360-430 nm. The decreased in intensity of fluorescence emission and excitation spectra were inversely correlated with the FFA content of the oil samples. This study demonstrates the potential of fluorescence spectroscopy in monitoring the deterioration of RBDPO during batch deep-fat frying

Antioxidative Activities of Selected Malaysian Herb Extracts during Accelerated Oxidation Test and Deep- Fat Frying

The potential use of selected Malaysian herb (Murraya koenigii, Curcuma longa, Citrus hystrix and Pandanus amaryllifolius) leaf extracts as natural antioxidant were evaluated in antioxidant assay, accelerated oxidation test and deep fat frying. They were analyzed for antioxidant activity using 1-1-diphenyl-2-hydrazyl (DPPH) radical- scavenging activity assay and linoleic acid model system. The extracts at different concentrations were added to refined, bleached and deodorized (RBD) palm olein and heated to frying temperature, analyzed for peroxide value, anisidine value, free fatty acid and oxidative stability index (OSI). From there, optimum concentration was chosen and 40 hr frying experiment was being carried out. The polyphenol content ranged from 101.4 mg in P. amaryllifolius to 116.3 mg C. longa. The antioxidative activity of the extracts in both assays followed the decreasing order of: C. longa> M. koenigii> C. hystrix> P. amaryllifolius. 2000 ppm was chosen as the optimum concentration to be used in deep frying experiment. Extracts of Pandanus amaryllifolius and Citrus hystrix exhibited protective activity towards RBD palm olein that was comparable to BHT (p>0.05) during frying. The extracts were useful in improving and also maintaining the sensory characteristics of French fries. The French fries treated with herb extracts were acceptable by panelists until day 5 of frying. The natural antioxidants significantly (p<0.05) lowered the rate of oil oxidation during deep- fat frying and maintaining the quality of French fries. They exhibited excellent heat- stable antioxidant properties are good natural alternative to existing synthetic antioxidants for the food industry

Frying Performance Of Palm Olein With Added Natural Antioxidant Mixtures And Acceptability Of Fried Potato Chips

A comprehensive study on the feasibility of use of natural antioxidants, namely rosemary and sage, together with citric acid acting as a synergist during repeated deep-fat frying process of potato chips in palm olein was carried out. The study was inclusive of evaluation of oxidative behaviour of these antioxidants, monitoring of physico-chemical changes of oil during frying, development of some new instrumental methods for detecting quality parameters of used oil, effect of addition of the antioxidants on organoleptic properties of fried product and relationship between quality indices of the oil and sensory acceptability of the fried product.Results showed that rosemary and sage extracts are feasible to be used in retarding the palm olein deterioration during repeated deep-fat frying of potato chips. The two natural antioxidants were proven to significantly (P<0.05) lower the rate of oxidation of the oil during frying, while having very good thermal resistance. Organoleptically, both rosemary and sage extracts could improve acceptability of fried potato crisps. There were significant correlations between sensory attributes of fried potato chips and quality parameters of palm olein used. Optimization study on the effect of use of the natural antioxidants during deep-fat frying on fatty acid composition of palm olein revealed that C 1 8:2 and C 16:0 fatty acids were the most important fatty acids for predicting changes in oil quality after frying. However, for optimization purposes, the use of the C 18:2/C 16:0 ratio best predicted the efficacy of natural antioxidants in preserving palm olein during deep-fat frying. This study also successfully developed instrumental methods for monitoring the physico-chemical changes of palm olein during repeated deep-fat frying. The alkaline contaminant materials (ACM) contents in palm olein could be determined spectrophotometrically at 540 nm, whereas the use of Fourier transform infrared (FTIR) spectroscopy to monitor changes in the iodine value, peroxide value and free fatty acid contents in palm olein during frying was found to be a viable alternative to the wet chemical methods, with FTIR providing rapid results taking less than 2 min per sample and minimum use of solvent and labour

Effects of frying by different frying oils on fatty acid profile of silver carp (Hypophthalmichthys molitrix)

The study aims to determine the influence of frying (shallow and deep) with olive, canola and sunflower oil on fatty acid composition of silver carp. Frying by olive oil and canola oil increased the monounsaturated fatty acids (MUFA) significantly (p<0.05) that consequently decreased saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) and ω-3 fatty acids. Frying by sunflower oil increased PUFA significantly (p<0.05), which caused to decrease in SFA and MUFA. The ω-6/ω-3 ratio of control samples (0.224) after shallow fat frying and deep frying, increased to 1.287 and 0.615; to 2.290 and 1.538; and to 9.381 and 5.950 by olive oil, canola oil and sunflower oil, respectively. Results suggest that frying oil can change the fatty acid composition of fish. The changes are depending to the kind of frying oil and method of frying which used

Analysis of energy use in crisp frying processes

Copyright @ 2010 Politecnico di Bari - BB PressWith increasing energy costs in industrial food frying processes it is essential to identify inefficiencies and minimise them. A way of achieving this is through the application of energy analysis and modelling techniques to characterise the process and investigate the interactions between the various operating and control parameters. The overall objective is to reduce energy consumption without compromising product throughput and quality. This paper provides a review of published work on heat and mass transfer in frying processes. Based on this, a simplified analysis of the key processes has been carried out using an energy balance model. The outputs of this model have been validated using data from an industrial crisp frying facility. The knowledge gained from this validation will be used to better understand and appreciate the energy flows in industrial frying processes and should lead to identification of losses and opportunities for energy recovery.The authors would like to acknowledge the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC), Grant NO. EP/G059799/1, for this project as well as the input from the industrial collaborators and academic collaborators from the Universities of Newcastle and Northumbria

Antioxidant activity of Citrus hystrix peel extract in RBD palm olein during frying of fish crackers

The Citrus hystrix peel extract (2,000 ppm) and butylated hydroxytoulene(BHT) (200 ppm) were added to the frying oil. The antioxidant activities were determined during deep fat frying of fish crackers for 4 consecutive days. Each frying period was for 5 h and intermittent frying at 180C with half an hour interval was carried out. The antioxidant activities were determined by measuring peroxide value (PV), p-anisidine value (AnV), totox value, iodine value (IV), percent free fatty acids, color and viscosity of the oil. Results indicated that the ethanol extract of the citrus peel exhibited antioxidant properties and therefore has a potential as one of the new sources of natural antioxidants