Effect of high pressure treatment on structure and properties of cellulose in eucalypt pulps

Abstract

Bleached acid sulphite and kraft Eucalyptus globulus pulps were subjected to treatment at high hydrostatic pressure (400 MPa during 10 min). The associated structural changes of cellulose were evaluated by X-ray scattering, solid-state NMR and infrared spectroscopy. The high pressure treatment promoted the growth of crystalline domains predominantly via lateral aggregation (cocrystallization) and, to some extent, due to the accretion of cellulose from noncrystalline domains (recrystallization). The treated pulps exhibited increment of the amount of strongly bound water and improved accessibility to amorphous domains. The high pressure treatment of dried sulphite pulp led to restoration, at least partially, of its swelling capacity thus diminishing the hornification features. Pressure treated dried sulphite pulp showed improved fibre bonding capacity at simultaneously increased bulk of the produced handsheets. The results obtained clearly showed the potential of high pressure treatments for the modification of cellulosic fibres in different applications.

Analysis of the lignocellulosic components of biomass residues for biorefinery opportunities

“…The sum of the area under the crystalline (101; 101 _ and 002 peaks, Fig. 1) adjusted peaks (I c ) and the amorphous broad band (I a ) was used to calculate the CI according to the following equation [37]:…”

Preservation of sliced cooked ham at 25, 30 and 37°C under moderated pressure (hyperbaric storage) and comparison with refrigerated storage

“…This is achieved by using pressures around 400-600 MPa at low or mild temperatures (<45 • C), usually from 3 to 10 min (Ramirez et al, 2009;Vercammen et al, 2011). Several other new applications of high pressure in food industry are being studied, as well as for biotechnological processes , like change of cellulose macromolecules properties (Figueiredo et al, 2010), changes of food proteins hydrosability (Correia et al, 2011), modulation of physiological processes, as potato tuber sprouting (Saraiva and Rodrigues, 2011), and more recently in the storage of food products, as an alternative to refrigeration (Fidalgo et al, 2013;Queirós et al, 2014;Segovia-Bravo et al, 2012).…”

A first study comparing preservation of a ready‐to‐eat soup under pressure (hyperbaric storage) at 25°C and 30°C with refrigeration

“…In addition to nonthermal pasteurization, in the last years high pressure has also raised interest for several other applications, as for example, to modify the proper-ties of macromolecules like cellulose (Figueiredo et al 2010), food proteins (Correia et al 2011), and modulate physiological processes (Saraiva and Rodrigues 2011). Another possible application, very recently reported, is food preservation under pressure at and above room temperature conditions, as a possible basically energetically costless alternative to refrigeration.…”