Pectinase hydrolysis of guava pulp: effect on the physicochemical characteristics of its juice

Abstract

The objective of this research is to assess the effect of enzymatic treatment of guava puree on the physicochemical parameters of the juice. Pectinases from Aspergillus niger were applied to the puree at 43 AE 3 C under constant stirring. Enzyme concentrations used were: 0.033 % (w/w), 0.055% (w/w), 0.078 % (w/w) and 0.1 % (w/w). For each enzyme concentration, the treatment times were varied from 3 -90 min. Physicochemical parameters of raw puree and enzymatically treated juice were determined. These were: viscosity, pH, electric conductivity, protein and polyphenol content, galacturonic acid content, color, TSS, and antioxidant capacity. Particle distribution, homogeneity of raw puree and juice samples dried extracts were assessed using a Field Emission Scanning Electron Microscopy (FESEM). A 91% viscosity decrease was recorded for each enzyme concentration after 3 min of enzyme reaction. That drecrase was accompanied by an increase in galacturonic acid content with increasing depectinization factors. Enzyme treatment of guava puree led to a decrease in pH, protein and polyphenol contents and an increase in conductivity and color. Analysis of FESEM images of guava samples bestowed a decrease in particle size, a scattering of particles in the medium, an increase in continuous phase proportion and an improvement of sample homogeneity with increasing values of processing parameters, due to the breaking-down of bigger particles and the solubilization during depectinization.

Effects of High-Pressure, Hydrothermal, and Enzyme-Assisted Treatment on the Taste and Flavor Profile of Water-Soluble Ginger (Zingiber officinale) Extract

“…The pectinase (cell wall degrading enzyme) used in this study was mainly used for clarification of fruit and vegetable juice. The clarification effect of plant extracts or juices can be explained as a result of high molecular compounds in plants forming oxidized proteins and partially removing neutral sugars (galacturonic acid monomers) [ 45 , 46 ]. Previous studies have demonstrated that pectinase is superior as an enzyme that breaks down the cell wall of ginger [ 29 ].…”

Clarification of white-fleshed guava juice by a fixed-angle conical rotor centrifuge laboratory and characterization of continuous disk stack centrifuges

“…Total soluble sugars (TSS), galacturonic acid, pectin, proteins contents; pH and electrical conductivity were determined as described by Ninga et al (2021).…”

“…Oligogalcturonates resulting from pectins hydrolysis are negatively charged; they could therefore be subject to ionic interactions with positively charged compounds such as proteins, yielding in the formation of complex particles (Jaarsveld et al 2005;Ninga et al 2021). During centrifugation, these particles, depending on their size, sedimentation velocity and the clari cation conditions, could settle forming the pellet.…”

“…Guava (Psidium guajava) is a well-known tropical and sub-tropical fruit. Originated from USA, Columbia, Peru and Mexico, it is nowadays widely spread in different countries in Asia, Africa and South America (Ninga et al 2021). Sometimes called "superfruit", it is well appreciated for its high vitamin A and C content (more than 4 times that of orange) (Akesowan and Choonhahirun 2013; Surajbhan et al 2012).…”

“…Tannin complexes could also be the result of polymerization of phenolic compounds into denser units (McLellan and Padilla-Zakour 2005). There could also be some interactions between proteins and oligalacturonates from pectins hydrolysis (Ninga et al 2021;Shomer et al 1999). These interactions can lead to particles formation coupled with stone cells, affecting juice stability during storage (Wu et al 2005).…”