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- Shelf‐life study of a Salicornia ramosissima vegetable salt: an alternative to kitchen saltPublication . Lima, Alexandre R.; Cristofoli, Nathana L.; Filippidis, Kyriakos; Barreira, Luísa; Vieira, MargaridaWaste of Salicornia ramosissima a halophyte plant used in gourmet cuisine, can be valorized after being dried and milled, becoming a vegetable salt, a healthier replacer of kitchen salt due to its lower sodium content (around 10-fold less) but still maintaining an intense salty taste. To study the shelf life of this vegetable salt from S. ramosissima, packed in a cylindrical aluminum box, an accelerated shelf-life testing (ASLT) was first carried out at 35, 40, 45, and 50 degrees C by monitoring color, moisture, and water activity (a(w)) throughout the storage period. Moisture and a(w) decreased at increasing temperature, but the color was not affected. The moisture sorption isotherms (MSIs) were next produced at 15, 25, 35, and 45 degrees C and relative humidity (RH: 6.5%-80%) using the static gravimetric method. Several mathematical models were tested to fit the MSI experimental data and finally the Oswin model was used to predict the moisture content. With this model, the isosteric heat was determined. A mass-balance model was used to predict shelf life and the equilibrium moisture content (M-e) during storage based on predetermined MSI and water vapor rate transmission (WVTR) data. The predicted shelf life of the package with and without adhesive tape around the lid was 35 and 80 days (25 degrees C, 75% RH) and 19 and 63 days (35 degrees C, 90% RH), respectively. Practical Applications By understanding the moisture sorption phenomenon in hygroscopic powders, this study can provide valuable data to the food industry dealing with such products. Being a microbiologically safe product due to its low a(w) and having color stabilized through previous drying, its mode of failure during storage proved to be the loss of its free-flowing capacity. A methodology to evaluate the shelf life of this hygroscopic product packed in a cylindrical aluminum box is described. There is a need to draw attention to the fact that, despite aluminum with a thickness of .23 mm is a very effective barrier to water vapor penetration, such package has an extremely small gap between the lid and body, which is hard to measure, yet allows water vapor to flow through the package at a rate that results in its shelf life being less than 3 months. Ways to overcome this issue are suggested.
- Comparative study of the production of cellulose nanofibers from agro-industrial waste streams of Salicornia ramosissima by acid and enzymatic treatmentPublication . Ribeiro Lima, Alexandre; Cristofoli, Nathana L.; Rosa Da Costa, Ana; Saraiva, Jorge A.; Vieira, MargaridaThe study of the suitability of two isolation processes to produce cellulose nanofibers (CNFs) from Salicornia ramosissima waste, with potential applicability as a reinforcing agent of polymeric composites was carried out. To separate the cellulose fibrils from the cell wall and obtain CNFs an alkaline treatment was applied followed by a bleaching treat-ment and, the insoluble residue was next hydrolyzed by either an acid treatment (AT) or an enzyme treatment (ET). SEM and TEM images indicated fiber exposure caused by both treatments. The diameter, length, aspect ratio, and polydispersity index, were measured for both CNFs. CNF (ET) showed high zeta potential values suggesting that ET produces more electrically stable and thinner nanofibers. The FTIR spectra revealed that both treatments effectively removed the amorphous components allowing the CNFs isolation, and XRD patterns evidenced the increase in the degree of crystallinity of both CNFs. Nonetheless, CNF(AT) presented a lower mechanical resistance due to its smaller particle size, compared to the CNF(ET). In summary, the (ET) could successfully isolate CNFs from the Salicornia waste, encouraging the use of this treatment, once when compared to (AT), it does not generate toxic residues, presents mild thermal conditions, and produces CNFs with higher-value applications.