Escalating the technical bounds for the production of cellulose-aided peach leathers: From the benchtop to the pilot plant.

This contribution falls within the context of sustainable functional materials. We report on the production of fruit leathers based chiefly on peach pulp, but combined with hydroxypropyl methylcellulose (HPMC) as binding agent and cellulose micro/nanofibrils (CMNF) as fillers. Increased permeability to moisture (from 0.9 to 5.6 g mm kPa-1 h-1m-2) and extensibility (from 10 to 17%) but reduced mechanical resistance (67-2 MPa) and stiffness (1.8 GPa-18 MPa) evidenced the plasticizing effect of peach pulp in HPMC matrix, which was reinforced by CMNF. A ternary mixture design allowed building response surfaces and optimizing leather composition. The laboratory-scale leather production via bench casting was extended to a pilot-scale through continuous casting. The effect of scaling up on the nutritional and sensory features of the peach leather was also depicted. The herein established composition-processing-property correlations are useful to support the large-scale production of peach leather towards applications both as packaging materials and as nutritional leathers.

On the effects of hydroxyl substitution degree and molecular weight on mechanical and water barrier properties of hydroxypropyl methylcellulose films.

In line with the increasing demand for sustainable packaging materials, this contribution aimed to investigate the film-forming properties of hydroxypropyl methylcellulose (HPMC) to correlate its chemical structure with film properties. The roles played by substitution degree (SD) and molecular weight (Mw) on the mechanical and water barrier properties of HPMC films were elucidated. Rheological, thermal, and structural experiments supported such correlations. SD was shown to markedly affect film affinity and barrier to moisture, glass transition, resistance, and extensibility, as hydroxyl substitution lessens the occurrence of polar groups. Mw affected mostly the rheological and mechanical properties of HPMC-based materials. Methocel® E4 M led to films featuring the greatest tensile strength (ca., 67 MPa), stiffness (ca., 1.8 GPa), and extensibility (ca., 17%) and the lowest permeability to water vapor (ca., 0.9 g mm kPa-1 h-1 m-2). These properties, which arise from its longer and less polar chains, are desirable for food packaging materials.