Detection of Vacuum Infusion of Pectinmethylesterase in Strawberry by Activity Staining

Abstract

Strawberry halves were infused with Valencia orange pectinmethylesterase (PME) under vacuum for 15 min at room temperature. Fruits were blotted onto pectin paper and stained for activity. Activity of PMEinfused fruit was about twice (0.36 unit/mL or 0.86 unit/mg protein) that of noninfused control (0.19 unit/mL) or water-infused control (0.16 unit/mL). Instron firmness values were not significantly different (P Յ Յ Յ Յ Յ 0.05) between noninfused and PME-infused fruit. Firmness of PME-infused fruit was about twice that of waterinfused control. Water-soluble pectin, chelator soluble pectin, alkaline soluble pectin, and total pectin ranged from 8.24 to 8.70, 3.24 to 4.56, 3.77 to 5.39, and 17.86 to 26.16 mg/100 mg alcohol insoluble solid (AIS), respectively, for all treatments.

Texture improvement of fresh and frozen mangoes with pectin methylesterase and calcium infusion

“…Vacuum infusion, as compared with atmospheric immersion, has the advantage of removing almost all interior gases that exist in the apoplastic spaces between cells; thus the enzyme solution has the ability to occupy these spaces and remains within the tissue after infusion 9. An increase in PME activity after vacuum infusion was also reported in previous research on strawberries and apples 6, 10, 14. The enzyme penetration is due to hydrodynamic phenomena allowing the external solution to fill the sample pores 10.…”

“…Addition of the enzyme pectin methylesterase (PME) and calcium has been reported to have beneficial effects on maintaining fruit firmness 5–8. Enzyme infusions potentially alter the texture, flavour and other sensory attributes of food items.…”

“…Banjongsinsiri et al 6 used a vacuum to infuse PME into strawberry halves, which resulted in a twofold increase in firmness in comparison with water‐infused controls; however, the firmness value reported was not significantly different from that of non‐infused fruit. Degraeve et al 5 reported the synergistic action of PME and calcium in the vacuum infusion solution on strawberry fruit texture.…”

Development of an immunological toolbox to detect endogenous and exogenous pectin methylesterase in plant-based food products

“…Infusion of exogenous PME has been proven to be effective in increasing firmness prior to processing, as was studied for peach (Javeri, Toledo, & Wicker, 1991), apple (Degraeve et al, 2003;Guillemin et al, 2006), raspberry (Degraeve et al, 2003), mango (Banjongsinsiri, Kenney, & Wicker, 2004b), eggplant (Banjongsinsiri, Shields, & Wicker, 2004) and strawberry (Banjongsinsiri et al, 2004a;Degraeve et al, 2003;Duvetter, Fraeye, et al, 2005;Fraeye et al, 2009;Van Buggenhout et al, 2006). PME demethoxylates pectin which can then form a rigid network through chelation of divalent cation, like calcium which can either be endogenously present or can be co-infused with PME.…”

“…In turn, these processes are determined by the porosity and permeability of the food matrices (Baker & Wicker, 1996;Saurel, 2002). These techniques have proven to be effective in infusing exogenous PME in tissues like for example strawberry, to reduce texture degradation during subsequent thermal processing or freezing (Banjongsinsiri, Kenney, & Wicker, 2004a;Degraeve, Saurel, & Coutel, 2003;Fraeye et al, 2009;Van Buggenhout et al, 2006).…”