The response of watercress (Nasturtium officinale) to vacuum impregnation: Effect of an antifreeze protein type I

Abstract

a b s t r a c tThe setting up of methodologies that reduce the size of ice crystals and reduce or inhibit the recrystallisation phenomena could have an extraordinary significance in the final quality of frozen products and consequently bring out new market opportunities. In this work, the effect of an antifreeze protein type I (AFP-I), by vacuum impregnation (VI), on frozen watercress was studied. The VI pressure, samples' weight, Hunter Lab colour, scanning electron microscopy (SEM), and a wilting test were analysed in this work.The water intake of watercress samples augmented with vacuum pressure increase. The results also showed that, independently from the vacuum pressure used, the Lab colour parameters between raw and impregnated samples were maintained, showing no significant differences (P > 0.05).A VI of 58 kPa, during 5 min, allowed impregnating the AFP-I solution (0.01 mg ml À1 ) into the watercress samples. The scanning electron microscopy (SEM) analysis showed the AFP-I impregnated frozen samples with better cell wall definition and rounded cell shape with smaller ice crystals compared with the control samples.The wilting test results corroborated that AFP-I is a valuable additive, since the leaves impregnated with AFP-I showed higher turgidity compared to the control samples.The present findings will help to better understand the effect of AFP-I, particularly, on frozen watercress microstructure and its importance as valuable food additive in frozen foods and mainly in leafy vegetables.

The Application of Vacuum Impregnation Techniques in Food Industry

“…However the formation of ice crystals leads to several physical damage and drip loss during thawing. Moreover, fluctuation of temperature along the cold chain may promote recrystallization phenomena leading to changes in size and shape of ice as well as their orientation (Zhao & Xie, 2004;Cruz et al, 2009). Vacuum impregnation was shown to be a useful method to incorporate in void phase of foods cryoprotectants and cryostabilizers, such as hypertonic sugar solution, antifreeze protein (AFP), high methoxyl pectin, etc.…”

“…In particular, grape must was able to reduce the freezable water content; instead pectin solution increased glassy transition temperature of liquid phase. Cruz et al (2009) carried out several experiments to evaluate the potential application of vacuum impregnation with antifreeze protein (AFP) with the aim to preserve the quality of watercress leaves. Results stated that samples treated with AFP showed small ice crystals in comparison with water impregnated samples, due to the ability of the proteins to bound water molecules modifying the natural ice crystal formation.…”

“…Since then, vacuum osmotic dehydration (VOD) was subject to a great number of scientific papers; in addition to VOD, the application of an initial vacuum pulse followed by the restoration of atmospheric pressure and the maintaining of food immersed into the osmotic solution for a long time was proposed as pulsed vacuum osmotic dehydration (PVOD). In the last 10 years a great number of industrial applications have been studied (Javeri et al, 1991;Ponappa et al, 1993;Rastogi et al, 1996;Fito et al, 2001a;Fito et al, 2001b;Gonzalez-Martinez et al, 2002;Betoret et al, 2003;Giraldo et al, 2003;Gras et al, 2003;Mujica-Paz et al, 2003a ;Mujica-Paz et al, 2003b;Zhao & Xie, 2004;Hofmeister, et al, 2005;Corzo et al, 2007;Silva Paes et al, 2007;Igual et al, 2008;Cruz et al, 2009). In general it is possible to consider two principal aims: 1.…”

Revisão: Proteínas anticongelantes – uma tecnologia emergente para o congelamento de alimentos

“…No trabalho realizado por Cruz et al (2009), também foi observada uma menor alteração na textura de agriões congelados, tratados previamente com uma solução de PACs do tipo I (peixes), quando comparadas a amostras controle. A amostra tratada com a PAC apresentou também uma coloração mais uniforme após o descongelamento.…”

“…Para outros alimentos, a adição pode se dar por diferentes métodos físicos, como mistura, injeção, imersão, revestimento, pulverização ou impregnação a vácuo, dependendo do alimento em questão (HASSAS ROUDSARI e GOFF, 2012). Para proteger tecidos vegetais do congelamento, por exemplo, é crucial que as PACs alcancem o apoplasto, uma vez que o gelo se forma preferencialmente nesse local (CRUZ et al, 2009).…”