Buriti Oil Emulsions as Affected by Soy Protein Isolate/High-Methoxyl Pectin Ratio, Oil Content and Homogenization Pressure

Pozadina istraživanja. Tehnologija emulgiranja prikladna je za inkapsulaciju, zaštitu i oslobađanje hidrofobnih biološki aktivnih tvari koje se koriste u prehrambenoj industriji, no emulzije nisu termodinamički stabilne. Dobri su rezultati postignuti s emulzijama stabiliziranim pomoću kompleksa proteina i polisaharida homogeniziranih pod visokim pritiskom. Poboljšana je stabilnost emulzija ulja u vodi rezultat elektrostatičkih kompleksa nastalih između proteina i polisaharida pri pH-vrijednostima nižim od izoelektrične točke proteina što adsorbiraju na granici faza ulje/voda. Osim toga, polisaharidi povećavaju viskozitet kontinuirane faze i time pridonose stabilnosti emulzije. Svrha je ovoga rada bila ispitati proizvodnju emulzija buriti ulja bogatog karotenoidima koristeći izolat sojinog proteina i pektin s velikim udjelom metoksila kao stabilizatore. Eksperimentalni pristup. Primjenom centralno složenog rotacijskog dizajna procijenili smo utjecaj sastava ulja, omjera izolata sojinog proteina i pektina s velikim udjelom metoksila te pritiska homogenizacije na stabilnost, veličinu kapljica, električnu vodljivost, električni naboj, mikrostrukturu i reološka svojstva emulzija. Rezultati i zaključci. Optimalna je emulzija dobivena primjenom 28 % buriti ulja, 55 % izolata sojinog proteina i pritiska homogenizacije od 380·105 Pa. Imala je manju prosječnu veličinu kapljica, nižu električnu vodljivost i veći modul negativnog naboja od ostalih emulzija, te je zadržala stabilnost tijekom najmanje sedam dana. Mehanički su spektri pokazali da je pri oscilirajućem smičnom opterećenju emulzija imala svojstva viskoelastičnog gela, a pri stabilnom je smičnom opterećenju pokazala osobine smičnog naprezanja. Novina i znanstveni doprinos. Optimirane emulzije buriti ulja stabilizirane pomoću izolata proteina soje i pektina s velikim udjelom metoksila mogu poslužiti kao zamjena za masti i pritom smanjiti energetsku vrijednost i povećati udjel karotenoida u prehrambenim proizvodima, poput mljekarskih i pekarskih proizvoda, sladoleda, umaka za salate i biljnog vrhnja.Research background. Emulsion technology is a suitable way of encapsulating, protecting and releasing hydrophobic bioactive compounds for application in food industries, but they are thermodynamically unstable systems. Good results have been achieved for emulsions stabilized by protein-polysaccharide complexes subjected to high-pressure homogenization. Improved stabilization of oil-in-water emulsions results from electrostatic complexes formed between proteins and polysaccharides at pH lower than the protein isoelectric point, which adsorb at the oil-water interface. In addition, polysaccharides contribute to emulsion stability by increasing viscosity of the continuous phase. The aim of this work is to investigate the production of carotenoid-rich buriti oil emulsions using soy protein isolate and high-methoxyl pectin as stabilizers. Experimental approach. Using a rotatable central composite experimental design, we assessed the effects of oil content, soy protein isolate/high-methoxyl pectin ratio and homogenization pressure on the stability, droplet size, electrical conductivity, electrical charge, microstructure and rheological behaviour of the emulsions. Results and conclusions. An optimized emulsion was produced with 28 % buriti oil, 55 % soy protein isolate, and homogenization pressure of 380·105 Pa. This emulsion was stable for at least seven days, presenting reduced average droplet size, low electrical conductivity and high modulus of negative charges. The mechanical spectra showed that the emulsion behaved as a viscoelastic gel under oscillatory, non-destructive shearing, whereas shearthinning behaviour took place under steady shear conditions. Novelty and scientific contribution. The optimized buriti oil emulsions stabilized by soy protein isolate and high-methoxyl pectin could be suitable for fat substitution, energy reduction and carotenoid enrichment in food products, such as dairy and bakery products, ice cream, salad sauces and vegetable-based cream

Qualidade dos pescados comercializados durante as festas do peixe de Dourados – MS / Quality of commercialized fish during the Dourados fish festivals - MS

 O objetivo deste trabalho foi realizar o monitoramento da qualidade do pescado fresco comercializado durante as festas do Peixe de Dourados nos anos de 2016, 2017 e 2018. A Princípio era realizado um monitoramento sanitário nas pisciculturas participantes da comercialização. Durante o período da festa. Realizava-se o monitoramento quanto as características organolépticas utilizando Método do Índice de Qualidade, pH e temperatura de cada espécie em comercialização, levando em conta sua origem. Em relação a questão sanitária de produção, Todas as pisciculturas visitadas atenderam os padrões para produção de alimento de qualidade. Quanto aos peixes, as somas dos pontos para o grau de frescor variaram entre 24 a 17 nos três anos avaliados, considerado de excelente a bom estado de frescor. O Valor de pH variou de 5,71 a 6,68, sendo que nesta faixa de pH, o produto entra na classificação de produto perecível, portanto, foi utilizado gelo para manutenção da qualidade e as temperaturas variaram de -0,9 a 6,8 ºC, nos anos avaliados. Em virtude destes resultados, Conclui-se que os pescados comercializados nas festas do peixe em Dourados de 2016, 2017 e 2018 atenderam os padrões de qualidade e segurança alimentar desejados

Quality characteristics and thermal behavior of buriti (Mauritia flexuosa L.) oil

Parámetros de calidad y comportamiento térmico del aceite de buriti (Mauritia flexuosa L.). En este trabajo realiza una completa caracterización del aceite de buriti. Las propiedades fisicoquímicas se llevaron a cabo de acuerdo con las metodologías AOCS y se midieron las propiedades termo-físicas usando un reómetro de esfuerzo controlado y un medidor de densidad electrónico digital. Se obtuvieron los contenidos de β-caroteno y tocoferol utilizando HPLC. Los ácidos grasos y las diferentes clases de acilgliceroles se determinaron utilizando GC y HPSEC, respectivamente, mientras que la composición de triacilglicéridos se estimó utilizando el software PrOleos. El comportamiento térmico (cristalización y fusión) se analizó utilizando un DSC. Los resultados ponen de manifiesto altos niveles de carotenoides totales con β-caroteno como mayoritario, tocoferoles totales, con α- y β-tocoferoles que representan el 91% del total, y ácidos grasos monoinsaturados representados principalmente por ácido oleico. Hay una estrecha relación entre la densidad y la viscosidad del aceite de buriti y las de los aceites de oliva. Los picos de cristalización y de fusión se dan a -43,06 °C y -2,73 °C, respectivamente. Estas propiedades permiten que el aceite de Buriti sea recomendado como una excelente alternativa para enriquecer alimentos con compuestos bioactivos.This work reports a complete characterization of buriti oil. Physicochemical properties were determined according to AOCS methodologies and thermophysical properties were measured using a controlled stress rheometer and a digital electronic density meter. β-carotene and tocopherol contents were obtained using HPLC systems. Fatty acids and acylglycerol classes were determined using GC and HPSEC systems, respectively, while triacylglycerol composition was estimated using the software PrOleos. Thermal behavior (crystallization and melting) was analyzed using a DSC. The results attested high levels of total carotenoids with β-carotene as the major one; total tocopherols contained α- and β-tocopherols which accounted for 91% of the total; and monounsaturated fatty acids were mainly represented by oleic acid. The results showed close agreement between density and viscosity of buriti and olive oils. The crystallization and melting peaks occurred at -43.06 °C and -2.73 °C, respectively. These properties enable Buriti oil to be recommended as an excellent alternative for enriching foods with bioactive compounds