Germán Bolívar

Bio: Germán Bolívar is an academic researcher from University of Valle. The author has contributed to research in topics: Chemistry & Fermentation. The author has an hindex of 2, co-authored 11 publications receiving 27 citations.

Mechanisms of action of novel ingredients used in edible films to preserve microbial quality and oxidative stability in sausages - A review

Abstract: Background Loss of organoleptic and microbial quality of sausages is a phenomenon mostly given by lipid oxidation, enzymatic autolysis, and presence of pathogenic microorganisms in meat, as well as inappropriate handling and storage conditions. The fast shortage of meat products unleashed by these processes may cause foodborne diseases and productivity losses. Therefore, the use of natural bioactive agents has been proposed as a suitable solution to address this problem. However, the phenomena exerted by specific molecules of these compounds to prevent the depletion of sausage quality are not clear enough. Scope and approach This review encompasses an overview of oxidative and bacterial spoilage in sausages, and a description of some biochemical mechanisms of novel bioactive compounds that have been included in film formulations to delay the shortage of these meat products. Key Findings and Conclusions Edible films containing bioactive compounds have been reviewed in order to analyze ingredients that may improve organoleptic and/or microbiological quality of sausages over time, highlighting relevant features concerning their antibacterial and antioxidant properties. Some of the main mechanisms of action have been related to pore formation and permeation of bacterial membrane, as well as depletion of its proton motive force, causing down-regulation of its metabolic functions and even cell death. On the other hand, hydroxyl groups from plant extracts may help to neutralize free radicals involved in lipid oxidation.

Use of an exopolysaccharide-based edible coating and lactic acid bacteria with antifungal activity to preserve the postharvest quality of cherry tomato

Abstract: One of the main causes of cherry tomato postharvest loss is diseases caused by food-contaminating fungi. Edible coatings (ECs) can preserve the quality of this crop and can serve as carriers of lactic acid bacteria (LAB), which have demonstrated inhibitory potential against phytopathogenic fungi. In the present study, the effectiveness of the LAB strain Lactiplantibacillus plantarum A6 incorporated into an EC based on exopolysaccharide from Weissella confusa JCA4 on the physicochemical and microbiological quality of cherry tomato was evaluated. The fruit were artificially inoculated with the fungi Aspergillus niger, Fusarium sp., and Rhizopus stolonifer to test the antifungal potential of the coating. The physicochemical and microbiological quality of cherry tomato was studied at two storage temperatures to calculate its shelf life. L. plantarum A6 remained viable both in the solution and on the surface of the fruit after coating, protecting the fruit against two of the three evaluated fungi (Fusarium sp. and Rhizopus stolonifer). The EC controlled weight loss, maintained firmness, and slowed the respiration rate of cherry tomato; the other physicochemical properties and the appearance of the fruit were not negatively affected. Based on these results, prolongation of shelf life was achieved by the application of the exopolysaccharide coating.

Reduction in saponin content and production of gluten-free cream soup base using quinoa fermented with Lactobacillus plantarum

Abstract: This study explored the effect of Lactobacillus plantarum 1 on the main anti-nutritional compound (saponin) and the rheological and physicochemical properties of quinoa doughs to produce a dehydrated soup base. A full factorial design using an ANOVA and a Tukey test (p < .05) was used to evaluate the effects of two factors: concentration of the inoculum (two levels) and fermentation time (four levels). The best experimental treatment was dried in a heat pump dryer at 40 and 50 °C, at 0.8 and 1.2 m/s, and drying processes were modeled using thin-layer math equations. Then, a mixture design was used to evaluate the interactions between the dried dough, rice flour and maltodextrin to select an optimum mix according to the objective function (average value of the three commercial cream soups). A base for the quinoa soup with a permissible saponins content and viscosity similar to that of trademark products was obtained. Practical applications The results of this research will help the food industry to cook high nutritional quality soups using gluten-free ingredients. Moreover, the use of lactic acid bacteria for fermenting quinoa is a good technique for improving the organoleptic characteristics and rheological properties of the final product. In addition, the culture medium was based on quinoa flour to help decrease the costs of the process compared with the price of commercial MRS broth.

Antagonistic Activity of Lactic Acid Bacteria Against Phytopathogenic Fungi Isolated from Cherry Tomato (Solanum lycopersicum var. cerasiforme).

Abstract: The postharvest deterioration of cherry tomatoes due to diseases caused by fungi is one of the main causes of the loss of this product. The objective of this study was to determine the antagonistic capacity by evaluating the antifungal power of nine strains of lactic acid bacteria (LAB) in vitro against the phytopathogenic fungi Aspergillus niger, Fusarium sp., and Rhizopus stolonifer isolated from cherry tomatoes (Solanum lycopersicum var. cerasiforme) and to measure the biosurfactant production capacity, its antagonism in vivo, and the production of organic acids. The results showed that seven of the nine strains were able to inhibit at least one of the three fungi isolated in the in vitro assay. In eight of nine strains, biosurfactant production was identified, and the strains Weissella confusa and Lactiplantibacillus plantarum A6 showed the highest antifungal activity in vitro and in vivo against the fungi evaluated, with the identification of organic acid production in both strains. LAB demonstrated the ability to inhibit cherry tomato fungi, thus emerging as an alternative to the use of chemical preservatives in the production of this fruit and being projected as a preservation technology for this type of product through the use of strains or their metabolites.

A review of active packaging in bakery products: Applications and future trends

Abstract: Background Rapid socio-economic development has allowed bakery products to gradually become a significant portion of people's daily diet throughout the world. However, microbial contamination and oxidation of lipids, as well as proteins in bakery products, may cause substantial economic losses and even threaten human health. The quality and safety properties of bakery products are highly dependent on packaging materials and technologies. Scope and approach The research into active packaging is a tremendous breakthrough towards solving these economic and safety problems while at the same time providing innovative methods to extend the shelf-life of bakery products. This article reviewed the factors affecting bakery products’ shelf-life and highlighted the different active packaging materials with myriad applications in bakery products, including antimicrobial, antioxidant, ethanol emitters and moisture absorbers packaging. Furthermore, consumer preferences towards active packaging, as well as the challenges and future trends in the development of active packaging in the bakery industry were also discussed. Key findings and conclusions By absorbing or releasing active compounds, active packaging systems can effectively delay or prevent microbial spoilage, reduce oxidation, and enhance the safety and quality of bakery products. Some innovative materials, such as stimuli-responsive antimicrobial materials, should be considered to successfully implement active packaging solutions in the bakery industry.

The sourdough fermentation is the powerful process to exploit the potential of legumes, pseudo-cereals and milling by-products in baking industry.

Abstract: In the era of fighting wastes and paying close attention to sustainability and new protein sources, legumes, pseudo-cereals and milling by-products deserve all the efforts for increasing their cons...

Fortification of edible films with bioactive agents: a review of their formation, properties, and application in food preservation.

Abstract: Biodegradable films constructed from food ingredients are being developed for food coating and packaging applications to create more sustainable and environmentally friendly alternatives to plastic...

Edible and Functionalized Films/Coatings—Performances and Perspectives

Abstract: In recent years, food packaging has evolved from an inert and polluting waste that remains after using the product toward an active item that can be consumed along with the food it contains. Edible films and coatings represent a healthy alternative to classic food packaging. Therefore, a significant number of studies have focused on the development of biodegradable enveloping materials based on biopolymers. Animal and vegetal proteins, starch, and chitosan from different sources have been used to prepare adequate packaging for perishable food. Moreover, these edible layers have the ability to carry different active substances such as essential oils—plant extracts containing polyphenols—which bring them considerable antioxidant and antimicrobial activity. This review presents the latest updates on the use of edible films/coatings with different compositions with a focus on natural compounds from plants, and it also includes an assessment of their mechanical and physicochemical features. The plant compounds are essential in many cases for considerable improvement of the organoleptic qualities of embedded food, since they protect the food from different aggressive pathogens. Moreover, some of these useful compounds can be extracted from waste such as pomace, peels etc., which contributes to the sustainable development of this industry.