http://dx.doi.org/10.4322/sc.2015.016

 

Comparative assessment of sugar in concentrated and nectar grape juices by refractometry, spectrophotometry and chromatography

Caldas, Bárbara Sthéfani; Constantino, Leonel Vinicius; Silva, Cyntia Helena Gomes Alves; Madeira, Tiago Bervelieri; Nixdorf, Suzana Lucy

Palavras-chave: arbohydrates, fructose, glucose, authenticity, HPLC-RID.

Resumo: Significant growth in juices production and consumption demand control methods, capable to measure fruit and sugars proportions for each kind of product. Basic consumer rights, require clear and appropriate composition and risks information’s on packaging. Despite this, Brazilians are often misleader, starting with juice’s nomenclature. By law, whole and concentrate juices must contain 100% of fruit without any addition. On the other hand, nectar, beverage ready for consumption, should be elaborated with a minimum of 50% of fruit, by adding water, sucrose, acidifiers and preservatives. Therefore, this study aimed to verify whether total sugars amounts of concentrate and nectar grape juices are comparable and consistent, as determined by 3 different techniques/methods – refractometry, spectrophotometry and chromatography, checking their applicability. Refraction (RF), the most applied in industrial control, employs oBrix direct reading in refractometer. Spectrophotometry measures glucose at 490 nm by conventional phenol-sulfuric method (FS-ESP). While, high-performance liquid chromatography determines fructose, glucose and sucrose levels using a refractive index detector (RID-HPLC). For purposes of total sugars concentration direct comparison, HPLC-RID levels were obtained by the sum of individual carbohydrates. The average of total sugars amount employing RF, ESP-FS, HPLC-RID was considered similar (Tukey p <0.05) for nectar (14.85±0.44 g 100 mL-1) and concentrate grape juice (61.74±2.60 g 100 mL-1), except for concentrate analyzed by ESP-FS (80.47±8.6 g 100 mL-1). The smallest variation levels was observed by RF (0.5 to 3.0%), followed by HPLC-RID (3.4 to 6.3%), with ESP-FS (8.4 to 17.2%) presenting the greatest dispersion. Thus, RF proved to be suitable for routine determination of total sugars, considering the precision, practicality and simplicity of use. HPLC-RID however has an additional differential besides providing total sugars content. Based on the chromatographic profile allows distinguishing between whole and concentrating juices, made only by fruit within fructose and glucose proportions naturally found in grape itself, from products added sucrose as nectar. This method consists therefore in an alternative tool that could be use in case of counterfeit suspected, to attest for authenticity and legislation compliance.


Referências Bibliográficas

1. Shayanfar, S.; Bodbodak S. Effect of different physicochemical de-tartration methods on red grape juice quality. Journal of Food Science and Technology, 51(12), 4084-4089, 2014. .
2. Grandizoli, C.W.P.S.; Campos, F. R.; Simonelli, F.; Barison, A. Grape juice quality control by means of 1H nmr spectroscopy and chemometric analyses. Química Nova, 37, 1227-1232, 2014. .
3. O’Byrne, D.J., Devaraj, S.; Grundy, S.M.; Jialal, I. Comparison of the antioxidant effects of Concord grape juice flavonoids and alpha-tocopherol on markers of oxidative stress in healthy adults. American Journal of Clinical Nutrition, 76(6), 1367-1374, 2002. .
4. Vinho, I.-I.B.D. Estudos científicos endossam benefício da uva e seus derivados à saúde. 2015. Disponível em: .
5. Xu, Y.; Simon, J. E.; Ferruzzi, M. G.; Ho, L.; Passinetti, G. M.; Wu, Q. Quantification of anthocyanidins in the grapes and grape juice products with acid assisted hydrolysis using LC/MS. Journal of Functional Foods, 4(4), 710-717, 2012..
6. Ma, B.; Chen, J.; Zheng, H.; Fang, T.; Ogutu, C.; Li, S.; Han, Y.; Wu, B. Comparative assessment of sugar and malic acid composition in cultivated and wild apples. Food Chemistry, 172, 86-91, 2015.< doi:10.1016/j.foodchem.2014.09.032>
7. Hermosín-Gutiérrez, I.; Castilho-Muñoz, N.; Goméz-Alonso, S.; Garcia-Romero, E. Flavonol Profiles for Grape and Wine Authentication. Progress in Authentication of Food and Wine. ACS Symposium Series, 1081, 113-129, 2011..
8. Nixdorf, S.L.; Hermosín-Gutiérrez, I. Brazilian red wines made from the hybrid grape cultivar Isabel: Phenolic composition and antioxidant capacity. Analytica Chimica Acta, 659(1–2), 208-215, 2010.< doi: 10.1016/j.aca.2009.11.058>
9. Mazza, G.; Francis, F. J. Anthocyanins in grapes and grape products. Critical Reviews in Food Science and Nutrition, 35(4), 341‑371, 1995. .
10. He, J.; Giusti, M. M. Anthocyanins: Natural Colorants with Health-Promoting Properties. Annual Review of Food Science and Technology, 1(1), 163-187, 2010.
11. Lona, A. O suco de Uva. Instituto Brasileiro do Vinho, 2009. Disponível em: .
12. IBRAVIN. Avaliação Setorial 2013, IBRAVIN – Instituto Brasileiro do Vinho, 17, 2013. Disponível em: .
13. Mello, L. M. R. Panorama da Vitivinicultura brasileira 2014. Revista Campo e Negócios, 2015. Disponível em: .
14. BRASIL, Decreto nº 6.871, de 4 de junho de 2009 – Regulamenta a Lei nº 8.918, de 14 de julho de 1991, que dispõe sobre a padronização, a classificação, o registro, a inspecão, a produção e a fiscalização de bebidas., S.d.A.J. Presidência da República – Casa Civil, Editor. 2009: Brasil. Disponível em: .
15. BRASIL, Instrução Normativa nº 12, de 4 de setembro de 2003, P.e.d.A. Ministério da Agricultura, Editor. 2003: Brasil. Disponível em: .
16. BRASIL, Instrução Normativa nº 24, de 30 de agosto de 2012, P.e.d.A. Ministério da Agricultura, Editor. 2012: Brasil. Disponível em: .
17. Santana, I.; Cabral, L. M. C.; Freitas, S. C.; Freitas, S. P.; Oliveira, A.; Matta, V. M. Composição química e centesimal de suco de uva concentrado por osmose inversa: influência da temperatura do processo. Embrapa Publicações, 2011. Disponível em: .
18. BRASIL, Instrução Normativa nº 01, de 7 de Janeiro de 2000, P.e.d.A. Ministério da Agricultura, Editor. 2000: Brasil. Disponível em: .
19. González-Mas, M. C.; Garcia-Riaño, L. M.; Alfaro, C.; Rambla, J. L.; Padilla, A. I.; Gutierrez, A. Headspace-based techniques to identify the principal volatile compounds in red grape cultivars. International Journal of Food Science & Technology, 44(3), 510-518, 2009.
20. Silva, R. N.; Monteiro, V. N.; Alcanfor, J. D. A. X.; Assis, E. M.; Asquieri, E. R. Comparação de métodos para a determinação de açúcares redutores e totais em mel. Food Science and Technology, 23, 337-341, 2003..
21. Guerra, C. C.; Zanus, M. C. Uvas Viníferas para Processamento em Regiões de Clima Temperado. 2003 [cited 2015 April 24]; Disponível em: .
22. Toaldo, I. M.; Cruz F. A.; Alves T. L.; Gois, J. S.; Borges, D. L. G.; Cunha, H. P.; Silva, E. L.; Bordignon-Luiz, M. T. Bioactive potential of Vitis labrusca L. grape juices from the Southern Region of Brazil: Phenolic and elemental composition and effect on lipid peroxidation in healthy subjects. Food Chemistry, 173(0), 527-535, 2015.
23. Wine, O. I. V. Evaluation by refractometry of the sugar concentration in grape musts, concentrated grape musts and rectified concentrated grape musts. Compendium Of International Methods Of Analysis – OIV. 2012. OIV. Disponível em: .
24. Kishio, S.; Aoyagi, Y. Cultivar- and Region-specific Differences in the Starch-Degrading Enzymes Produced During Rice Soaking. Nippon Shokuhin Kagaku Kogaku Kaishi, 61(6), 232-243, 2014.
25. Gusakov, A.V.; Kondratyeva, E. G.; Sinitsyn, A. P. Comparison of Two Methods for Assaying Reducing Sugars in the Determination of Carbohydrase Activities. International Journal of Analytical Chemistry, 2011, 4, 2011. .
26. Galvão, M. A. M.; Ferreira, M. R. A.; Nunes, B. M.; Santana, A. S. C. O.; Randau, K. P.; Soares, L. A. L. Validation of a spectrophotometric methodology for the quantification of polysaccharides from roots of Operculina macrocarpa (jalapa). Revista Brasileira de Farmacognosia, 24(6), 683-690, 2014.
27. Wrolstad, R. E.; Acree, T. E.; Decker, E. A.; Penner, M. H.; Reid, D. S.; Schwartz, S. J.; Shoemaker, C. F.; Smith, D. M.; Sporns, P. Water, Proteins, Enzymes, Lipids, and Carbohydrates. Handbook of Food Analytical Chemistry, 653-660, 2005. Disponível em: .
28. Zhang, Q.; Bailey, B.; Thomas, D.; Plante, M.; Acworth, I. Direct Carbohydrate Analysis in Beverages and Foods Using Pulsed Amperometric Detection or Charged Aerosol Detection. Thermo Fisher Scientific Publication, 7, 2015. Disponível em: .
29. BRASIL, Decreto nº 2.181, de 20 de março de 1997 – Regulamenta a Lei nº 8.078, de 11 de setembro de 199, que dispõe sobre o Código de Defesa do Consumidor, Redação dada pela Lei nº 12.741, de 2012, S.d.A.J. Presidência da República – Casa Civil, Editor. 2012: Brasil. Disponível em: .
30. Duarte-Delgado, D.; Narváez-Cuenca, C. E.; Restrepo-Sánchez, L. P.; Kushalappa, A.; Mosquera-Vásquez, T. Development and validation of a liquid chromatographic method to quantify sucrose, glucose, and fructose in tubers of Solanum tuberosum Group Phureja. Journal of Chromatography B, 975(0), 18-23, 2015. < http://dx.doi.org/10.1016/j.jchromb.2014.10.039>.
31. Rizzon, L. A.; Miele, A. Analytical characteristics and discrimination of Brazilian commercial grape juice, nectar, and beverage. Food Science and Technology, 32, 93-97, 2012. Disponível em: < http://dx.doi.org/10.1590/S0101-20612012005000015> Scientia Chromatographica 2015; 7(1):53-63 63.