Micronized natural talc affects the proteins and pectic cell wall polysaccharides during “Hojiblanca” virgin olive oil extraction

Abstract

This work studies how using MNT affects cell wall polysaccharides and proteins of “Hojiblanca” paste during virgin olive oil extraction. Four doses of MNT were assessed: 0, 0.25, 0.5, and 1%. Three pectic fractions were extracted from alcohol insoluble solids (AIS): water‐soluble pectin (WSP), chelate‐soluble pectin (CSP), and non‐soluble pectin (NSP). In general, the content of the three pectic fractions decreased throughout the kneading step. This indicated a significant degradation and solubilization of pectins during processing. The same trend was observed for protein content and total pectin content while AIS yield increased. Addition of MNT at doses lower than 0.5% favored the formation of a chemical bound through electrostatic interactions between proteins and pectic polysaccharides which are held together and adsorbed onto the talc surface giving a decrease in their content. Higher MNT doses (1%) produced the opposite behavior. The lowest dose of MNT (0.25%) reduced the oil losses in the pomace. A certain tendency for the loss of oil in the pomace to decrease as the amount of total pectin and protein decreased was observed, indicating that the oil yield is at least in part, related to the pectin and protein content depending on the dose of MNT added during malaxation step. Practical application: We have demonstrated that the use of talc during the malaxation step greatly lessens the effect of the pectic substrates and proteins, principal emulsifier agents that influence the formation of oil‐in‐water emulsions during oil extraction process and enhance the extraction of the oil from the mesocarp cells by reducing its loose in the pomace. Excess of talk addition presented a reverse effect, though. It is, therefore, of the utmost importance that the information contained in this study is fully taken into account to establish the suitable dose of talc that should be applied when difficult pastes are formed during malaxation step and which at least partially depends on the content of proteins and pectin compounds of the processed olive paste. Proteins and pectic cell wall polysaccharides as affected by talc addition during virgin olive oil extraction.

Co-Processed Olive Oils with Thymus mastichina L.—New Product Optimization

“…This decrease may be ascribed to oil adsorption to the lignocellulosic material of thyme during malaxation operation, hindering mechanical oil extraction. A similar situation was referred by other authors, which was explained by an absorption/adsorption process [42,43]. For water addition, a positive linear effect was found (p = 0.05), meaning that an increase in water concentration will improve the extraction yield.…”

Olive Oil Processing: Current Knowledge, Literature Gaps, and Future Perspectives

“…It was proposed that the action of talc is based on the adsorption of pectins and of pectic‐protein electrostatic complexes on its surface, which act as emulsifiers in the olive paste. This adsorption was also shown for pectins in a model system (Aguilera et al, ; Sadkaoui et al, , ). Crucial variables affecting oil extraction yield except talc dosage are particle size and calcium carbonate rate, as suggested in laboratory experiments (Moya et al, ; Sadkaoui et al, ).…”

“…According to the literature, the malaxation variables that have a major impact on the extraction yield and the quality of the final oil are the duration (time) and temperature of the process, the composition of the atmosphere in the malaxer (Abenoza et al, ; Aguilera et al, , ; Aiello et al, ; Amirante et al, ; Angerosa et al, ; Carrapiso et al, ; Catania et al, ; Di Giovacchino et al, ; Gomez‐Rico et al, ; Jolayemi et al, ; Kalua et al, ; Leone et al, , ; Lercker et al, ; Lukić et al, ; Malheiro et al, ; Masella et al, ; Migliorini et al, ; Parenti et al, ; Raffo et al, ; Sánchez‐Ortiz et al, ; Servili et al, , ; Stefanoudaki et al, ; Taticchi et al, ; Vezzaro et al, ), the extent of cell damage and the degree of emulsification produced in the crushing stage (Preziuso et al, ), and the properties of the paste (e.g. rheological properties), as well as the addition of lukewarm water (Carrapiso et al, ) and coadjuvants (Aguilera et al, ; Caponio et al, ; Carrapiso et al, ; Clodoveo, ; Cruz et al, ; Espinola et al, ; Moya et al, ; Sadkaoui et al, , b; Squeo et al, ; Tamborrino et al, ). Furthermore, modifications of the classical malaxers and pretreatment processes showed an effect on the olive oil properties and extraction yield (Abenoza et al, ; Almeida et al, ; Bejaoui et al, , b, ; Clodoveo, ; Clodoveo et al, , ; Clodoveo and Hachicha Hbaieb, ; Juliano et al, ; Leone et al, , ; Puértolas and Martínez De Marañón, ).…”

“…The addition of coadjuvants during malaxation is recommended to help break down oil/water emulsions and consequently make oil extraction easier and more efficient (Aguilera et al, ; Ben Brahim et al, ; Ben‐David et al, ; Canamasas and Ravetti, ; Caponio et al, , ; Carrapiso et al, ; Cruz et al, ; De Faveri et al, ; Espinola et al, , ; Majetić Germek et al, ; Moya et al, ; Pérez et al, ; Sadkaoui et al, , , b; Squeo et al, ; Tamborrino et al, ). The most common coadjuvants examined in the literature are talc, calcium carbonate, salt, and enzymes.…”

“… Studies in pilot/industrial scale : Aguilera et al (, ); Caponio et al (); Caponio et al (); García et al (); Moya et al (); Ranalli and De Mattia (); Ranalli et al (, , b, , b, c, ); Sadkaoui et al (, ); Sharma et al (); Squeo et al (); Tamborrino et al ().…”