Jumbo squid (Dosidicus gigas) is an important commercialized fishery in Mexico; however, during its post‐catch processing, several physicochemical changes occur in flesh, which could result in texture modifications. In this research, changes in water‐holding capacity, protein solubility (PS), firmness, fibrils microstructure, and color of squid muscle (mantle, fins, and arms) during cooking (30 min at 100 °C) were evaluated. Throughout cooking were exhibited different shrinkage and weight loss behavior among three anatomical regions (p < .05). After cooking, PS of muscle from fins and arms remained similar, meanwhile, mantle muscle PS decreased 75%. Shear force (SF) magnitude order (p < .05) registered in fresh muscle was fins > arms > mantle, whereas at ending cooking, mantle muscle required the lowest SF. Microscopic analysis revealed a major quantity of collagen fibers in fins and arm muscle suggesting its possible relation to their hardness, in both fresh and cooked state. Practical applications Jumbo squid (Dosidicus gigas) is an important marine resource in Mexico and many Asiatic and European countries. Its muscle (fins, arms, and mantle) edible items are commercialized and consumed in fresh, brined, and cooked presentations. Squid muscle protein structures (fibril and stromal) are organized different than fish as well as beef, pork and poultry; therefore its textural, physicochemical and sensorial (quality parameters) changes induced by cooking are distinctive. Squid meat acceptance by consumers is related mainly by texture than the taste or color attributes. Therefore, from economic point of view of domestic and large‐scale markets, the establishment of best cooking conditions of squid became essential.

Chymotrypsin was purified from jumbo squid hepatopancreas (HP) with 2.4-fold and yield 1.9%, and characterized with a molecular weight of 31 kDa, as estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Chymotrypsin effect over collagen extracted from the mantle, fins and arms of the jumbo squid was evaluated. The enzyme exhibited the maximum activity at pH 7 and 65°C using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as a substrate and it was identified using the specific inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and phenyl methyl sulfonyl fluoride (PMSF), showing residual activities of 6% and 0%, respectively. Furthermore, high activity was observed in the pH range of 4.0 to 8.0. Purified enzyme showed a moderate activity using muscle collagen as a substrate. Although further research is needed, the results suggest that the enzyme has a potential application where acidic or slightly alkaline conditions are needed.

The use of halophytes such as Salicornia bigelovii represents an alternative with economic potential for desert agriculture and coastal areas. However, the success in the establishment of commercial plots has been limited by the low germination percentages of this species. Propagation using plant cuttings represents a viable and rapid alternative to this problem. The formation of functional roots is fundamental in the propagation of plant cuttings and has been achieved through the application of chemical growth regulators. The application of chitosan in some crops has evidenced to be an alternative for the germination process and an enhancer of harvest performance; however, there are no studies that evaluate its effect on the halophyte S. bigelovii. The objective of this research was to evaluate the effect of marine-derived chitosan and indole butyric acid as root-promoting agents in cuttings of Salicornia bigelovii. The concentrations (individually and combined) of chitosan at 100 and 50% and indole butyric acid were applied at a rate of 0.937 and 1.25 g kg‑1. A completely randomized design of nine treatments and f ive repetitions was used and 225 experimental units were evaluated. The following variables were measured: root length, fresh weight and total dry weight of the root, and number and length of new shoots. The results showed that the most eff icient treatment was 100% chitosan + 0.937 g kg-1 indole butyric acid, promoting the production of photosynthetic shoots up to 800%. These results indicate that it is feasible to achieve the propagation of Salicornia by means of cuttings using marine-derived chitosan as a growth promoter.

Torres-Arreola (2018) Physicochemical changes of pepsin-solubilized and insoluble collagen in jumbo squid (Dosidicusgigas) muscle after cooking process,

Ruíz Alvarado y E.O. Rueda-Puente. ECOFISIOLOGÍA Y BIOQUÍMICA DE Salicornia bigelovii (Torr.) POR EFECTO DE QUITOSANO-AIB BAJO CONDICIONES DEL DESIERTO DE SONORA. ECOPHYSIOLOGY AND BIOCHEMISTRY OF Salicornia bigelovii (TORR.) BY EFFECT OF CHITOSAN-AIB EFFECT UNDER SONORA DESERT CONDITIONS.