THE EFFECTS OF RADIOFREQUENCY HEATING ON THE AMINOACIDS CONTENT OF WHOLE WHEAT BREAD, GRAHAM BREAD AND WHITE BREAD Mustãţea G.S., Miteluţ A.C., Ştefãnoiu G.A., Popa E.E., Drãghici M., Popa M.E., Cramariuc R., Balaurea-Chirilov A.M., Mãriuţ C ., Mohan G., Culeţu A.
1. INTRODUCTION 2. MATERIALS AND METHODS TABLE OF CONTENTS 3. RESULTS AND DISCUSSIONS 4. CONCLUSIONS
OBJECTIVE Analysis of amino acids content in 3 types of bread : White bread , Whole Wheat bread and Sylvester Graham bread before and after RF treatment .
INTRODUCTION Bread is one of the most popular and important food products in many countries due to its significant nutritional, sensory, and textural characteristics, but it has a relative short-life. (Yi et al., 2009). Several methods can be applied for extending shelf-life of breads concerning both recipe formulation and storage conditions. Radiofrequency treatment (RF) is one of these methods; the results are promising and show that RF heating represents a good perspective for increasing shelf life of bread but the effects on nutritional value of the treated products are not well established.
MATERIALS AND METHODS 3 types of bread : BREAD SAMPLES White bread Whole Wheat bread Sylvester Graham bread The samples had a thickness of 7 cm, a height about 8 cm and they were packed individually.
MATERIALS AND METHODS RADIOFREQUENCY TREATMENT To develop RF treatment protocols was used a 27.12 MHz RF laboratory system. To evaluate the possible undesirable effects of the treatment on the amino acids content of product, the samples were heated until was reached the temperature of 100ºC in the center of the product . RF 27.12 MHz system - demonstrative model The measurement system of temperature by IR, RP 15 model
MATERIALS AND METHODS AMINO ACIDS DETERMINATION METHOD Dionex ICS3000 system: 1. Autosampler 2. AminoPac PA10 column 3. Dual pump 5. Eluent distributor 4. Computer (with the Chromeleon 6.80 software) Hydrolysis in HCl 6N – 24hours / 110 °C SAMPLE PREPARATION
RESULTS AND DISCUSSIONS The samples were evaluated at two different moments: T 0 - initial moment (control and treated samples at 100ºC) T 10 – after 10 days from the treatment (control and treated samples at 100ºC ), in order to observe the effects of the radiofrequency treatment on the amino acids content. P1 – control (T 0 ); P2 - sample treated at 100ºC (T 0 ); White bread : P1 * - control (T 10 ); P2 * - sample treated at 100ºC (T 10 ); P3 – control (T 0 ); P4 - sample treated at 100ºC (T 0 ); Whole wheat bread : P3 * - control (T 10 ); P4 * - sample treated at 100ºC (T 10 ); P5 – control (T 0 ); P6 - sample treated at 100ºC (T 0 ); Graham bread : P5*- control (T 10 ); P6*- sample treated at 100ºC (T 10 ).
RESULTS AND DISCUSSIONS AMINOACIDS CONTENT IN WHITE BREAD (mg/100g) P1 P2 ARG ARG 34.2 33.7 LYS LYS GLU 21.2 27.8 114.1 GLU 114.7 T 0 MET MET 126.6 147.9 PHE PHE 4.9 5.4 100 ° C control P2* P1* ARG ARG 41.7 41.7 LYS LYS GLU GLU 28.8 20.9 105.7 111.2 T 10 MET MET 122.9 116.4 PHE PHE 4.7 5.5
RESULTS AND DISCUSSIONS AMINOACIDS CONTENT IN WHOLE WHEAT BREAD (mg/100g) CYS CYS 1.9 2.3 P3 P4 PHE PHE 61.0 50.9 ARG ARG 129.3 HIS 146.5 HIS T 0 38.2 44.7 ALA ALA 13.9 14.4 LYS LYS 131.0 118.7 100 ° C control CYS CYS 1.7 2.9 P4* P3* PHE PHE 59.3 47.6 HIS HIS ARG ARG T 10 37.1 44.6 144.3 150.1 ALA ALA 14.9 17.1 LYS LYS 126.7 112.0
RESULTS AND DISCUSSIONS AMINOACIDS CONTENT IN GRAHAM BREAD (mg/100g) ASP CYS TYR ASP CYS TYR 2.3 P6 9.4 8.8 3.5 2.4 P5 5.8 ARG ARG PHE PHE 127.1 119.5 121.3 142.1 T 0 ALA ALA 113.1 118.6 LYS LYS 318.0 275.1 100 ° C control ASP CYS TYR ASP CYS TYR 9.6 3.7 2.3 9.6 6.4 2.6 P6* P5* ARG ARG PHE PHE 133.4 118.8 143 124.5 T 10 ALA ALA 119.4 LYS 117.3 LYS 307.9 262.4
CONCLUSIONS Studies were conducted to evaluate the effects of RF heating on amino acids profile of 3 types of bread. Not all the amino acids were quantified; this may be due to oxidation of some amino acids during sample preparation, as well as insufficient separation. Preliminary measurements indicated small differences between bread samples, before and after RF treatment, so the influence of the treatment did not influence the amino acid content and also does not influence the nutritional characteristics of the product.
ACKNOWLEDGEMENTS This work was supported by Partnerships in priority areas Programme, PCCA Contract no. 164 / 2014, RAFSIG and grant of the Romanian National Authority for Scientific Research and Innovation, CNCS/CCCDI – UEFISCDI, project number 14/2017, within PNCDI III http://rafsig.usamv.ro/
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