Advances in preservation of fruits and vegetables with bioactive coatings

Bioactive compounds are a large group of compounds (antimicrobials, antioxidants, nutrients, etc.), but its use in edible fi lms and coatings for application on fruits and vegetables has been very important because nowadays the consumers demand fruits and vegetables that are fresh, healthy, high quality and easy to prepare. A number of investigations have shown that the use of additives in edible fi lms and coatings improve its functionability and provide compounds for human health. However, it is necessary to continue research that can generate specifi c or tailor-made edible fi lms and coatings for each product with the best characteristics for preservation. In this review we present and analyze the concepts, progress and perspectives in the design and application of edible fi lms and coatings for fruits and vegetables in order to defi ne the challenges and opportunities that this topic of study in the fi eld of science, technology and food engineering.Los autores agradecen el apoyo fi nanciero brindado por el Consejo Nacional de Ciencia y Tecnología (CONACYT), a la Dra. Blanca Valdivia Urdiales por el apoyo brindado en la escritura de este manuscrito y al M.C. Jorge Alejandro Aguirre Joya por la edición del mismo

Evaluation of autohydrolysis pretreatment using microwave heating for enzymatic saccharification of corn residues

Pretreatment of lignocellulosic materials (LCMs) is one of the most critical stages in the production of 2G bioethanol, this stage allows to maximize the production of fermentable sugars in the enzymatic saccharification process (ESP). Recently the microwave heating (MH) have been studied for enhanced the LCMs pretreatment, this technology reduces the energy requirements in the process, due to the fast heat transfer and it has allowed to redefine a lot of reactions which the thermal factor plays an essential role in the process. In this work were evaluated the effects of autohydrolysis pretreatment from corn residues using microwave heating and the pretreated solids as substrate in the enzymatic saccharification. The autohydrolysis pretreatment was performed using water as catalyst, the time (10, 30 and 50) and temperature (160, 180 and 200 ºC) were evaluated and the pretreated solids were used in the ESP. The enzymatic saccharification were performed with a working volume of 50 mL, 50 mM citrate buffer (pH 4.8), 2% (w/v) sodium with a cellulose concentration of 1 % (w/v) and incubated at 50 °C. The CellicCTec2 - cellulase was used with a loading of 20 FPU/g. This work showed that microwave autohydrolysis processing is an efficient pretreatment producing a solid enriched with cellulose (63.67±0.91) . The solid pretreated at 200 °C for 10 min was the best condition for saccharification yield (96.95% ± 0.79). This autohydrolysis pretreatment using microwave heating and enzymatic saccharification is a good alternative to obtain fermentable sugars for bioethanol production

Polyphenols and sugars recovery from autohydrolysis of pineapple waste

[Excerpt] The aim of this research was to evaluate the influence of temperature, time and mass/ volume ratio on the release of sugars and polyphenols using an autohydrolysis procedure from pineapple waste. A Box-Bhenken design was used with three factors (time, temperature and mass/volume ratio) and three levels was used. All treatments were performed in triplicate. Nine central points were used. For autohydrlosysis treatments, an oil bath was used [1]. After autohydrolysis, liquid phases or hydrolysates were analyzed for glucose and fructose concentration by high performance liquid chromatography (HPLC) [2]. The FolinCiocalteu assay was used to measure total polyphenols of hydrolysates [3] and HPLC to identify these molecules [4]. (...

Bioactive compounds (phytoestrogens) recovery from Larrea tridentata leaves by solvents extraction

Methanol, ethanol, and acetone at four different concentrations (90%, 70%, 50%, and 30% v/v) were used for extraction of phytoestrogens (nordihydroguaiaretic acid (NDGA), kaempferol, and quercetin) from Larrea tridentata leaves. Besides the phytoestrogens extraction, the antioxidant potential, and the contents of total phenols, flavonoids, and protein in the produced extracts were also determined. The solvent and concentration used for extraction strongly affected the phytoestrogens recovery. The highest NDGA, quercetin, and kaempferol contents (46.96 ± 3.39, 10.46 ± 1.01, and 87.00 ± 6.43 mg/g DW plant, respectively) were recovered using 90% (v/v) methanol. All the produced extracts showed antioxidant capacity, but those obtained using 70% and 90% (v/v) methanol had significantly higher (p < 0.05) FRAP (ferric reducing antioxidant power) values (2.55 ± 0.09 and 2.73 ± 0.11 mM FE(II)/g DW plant, respectively) than the remaining ones. Extract produced by using 90% (v/v) methanol contained also the highest contents of total flavonoids (19.29 ± 0.79 mg QE/g DW plant) and protein (131.84 ± 6.23 mg/g DW plant), and elevated total phenols concentration (263.60 ± 25.78 mg GAE/g DW plant).The authors gratefully acknowledge FCT (Contract/Grant Nos: SFRH/BD/40439/2007 and SFRH/BPD/38212/2007) for financial support of this work

Physicochemical characterization and extraction of bioactive compound from Larrea tridentata leaves

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/1096

Effect of extraction solvents on the content of bioactivecompounds from Larrea tridentata leaves

Three organic solvents (methanol, ethanol, and acetone) at four different concentrations (90, 70, 50, and 30% v/v) were used for extraction of hormone-like phenolic compounds (phytoestrogens) from Larrea tridentata leaves, namely, nordihydroguaiaretic acid (NDGA), kaempferol and quercetin. Besides the phytoestrogens extraction the antioxidant potential and the content of total phenols in the produced extracts were also determined. Phytoestrogens recovery varied considerably according to the solvent and concentration used for extraction. The highest NDGA, quercetin and kaempferol contents (46.96 ± 3.39, 10.46 ± 1.01 and 87.00 ± 6.43 mg/g DW plant, respectively) were recovered using 90% (v/v) methanol. All the produced extracts showed antioxidant capacity, but those obtained using 70% and 90% (v/v) methanol had significantly higher (p<0.05) FRAP (ferric reducing antioxidant power) values (2.55 ± 0.09 and 2.73 ± 0.11 mM FE(II)/ g DW plant, respectively) than the remaining ones. These findings allow concluding that 90% (v/v) methanol can be successfully used for the bioactive compounds (phytoestrogens) recovery from Larrea tridentata leaves

Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

The development of a feasible biorefinery is in need of alternative technologies to improve lignocellulosic biomass conversion by the suitable use of energy. Microwave heating processing (MHP) is emerging as promising unconventional pretreatment of lignocellulosic materials (LCMs). MHP applied as pretreatment induces LCMs breakdown through the molecular collision caused by the dielectric polarization. Polar particles movement generates a quick heating consequently the temperatures and times of process are lower. In this way, MHP has positioned as green technology in comparison with other types of heating. Microwave technology represents an excellent option to obtain susceptible substrates to enzymatic saccharification and subsequently in the production of bioethanol and high-added compounds. However, it is still necessary to study the dielectric properties of materials, and conduct economic studies to achieve development in pilot and industrial scale. This work aims to provide an overview of recent progress and alternative configurations for combining the application of microwave technology on the pretreatment of LCMs in terms of biorefinery.Financial support is gratefully acknowledged from the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Cluster of Bioalcohols (Ref. 249564). This study was supported by the Secretary of Public Education of Mexico PROMEP project/103.5/13/6595 – UACOAH-PTC-292 and PROMEP project/DSA/103.5/14/10442 – UACOAH-PTC-312. We gratefully acknowledge support for this research by the Mexican Science and Technology Council (CONACYT, Mexico) for the infrastructure project - INFR201601 (Ref. 269461) and CB-2015-01 (Ref. 254808). The author A. Aguilar-Reynosa thanks to Mexican Science and Technology Council (CONACY, Mexico) for master fellowship support

Characterization of k-carrageenan/Locust bean gumbased films with b-carotene emulsion

New bio-based materials have been exploited to develop biodegradable and edible films as an effort to extend shelf life and improve quality of food while reducing packaging waste. The objective of this study was to investigate physicochemical properties of k-carrageenan/locust bean gum (k-car/LBG) films with different bcarotene emulsion concentrations. To prepare oil-in-water emulsions, b-carotene (0.03% v/v) was dissolved in mediumchain triglycerides (MCTs), and the solution was mixed (1:9 v/v) with a pectin solution (3% w/v) as emulsifier. Film forming solutions were prepared by adding b-carotene emulsion (0-3% w/w) into the k-car/LBG solution (40/60% w/w) with 0.3% (w/v) of glycerol. Films with different b-carotene concentrations were characterized in terms of optical, mechanical and barrier properties and compared with control films without bcarotene. The results suggested that mechanical, physical and barrier properties of k-car/LBG films were influenced by the presence of b-carotene. Results showed that addition of b-carotene to the k-car/LBG films studied resulted in significant decrease (p<0.05) in water vapour transmission rate values. Film opacity values (ranging from 4.9 to 12.5 %) increased when b-carotene was incorporated to the film. Therefore, b-carotene emulsions have potential to be used as a natural additive on kcar/LBG films, particularly in the food packaging industry