Servicios personalizados
texto en 
Inglés (pdf)
Articulo en XML
Referencias del artículo
Curriculum ScienTI
Enviar articulo por email
Citado por SciELO 
Similares en
SciELO 
Permalink
Orito banana is produced throughout the year in the Ecuadorian Amazon region. After consuming this fruit, residues are generated, including peel and rachis, which do not receive adequate treatment for their use in animal feed. Different studies have reported the presence of proteins, lipids, fiber and compounds with antioxidant capacity in these by-products, as well as phytochemical compounds with activity against free radicals (Blasco-López and Gómez-Montaño 2014).
Studies carried out with banana peel and pulp reported that these by-products contain several antioxidant compounds, such as gallocatechin, alkaloids, flavonoids, tannins, phenolic compounds, and dopamine (Blasco-López and Gómez-Montaño 2014). In the nature, alkaloids and tannins inhibit nutrient absorption, and for their efficient use, drying, cooking and fermentation with lactic bacteria (LAB) are recommended. Fermentation of agricultural by- products with LAB is one of the important processes for obtaining phenolic compounds with an antioxidant effect (Lin et al. 2018). The objective of this study was to determine the physicochemical and organoleptic indicators of orito banana (Musa acuminata AA) rachis silage, treated with whey.
The study was carried out in the microbiology and bromatology laboratories of the Universidad Estatal Amazónica (UEA), main campus, located at km 2 ½, via Puyo-Tena, in Puyo city, canton and province of Pastaza. To make the silage, orito banana rachis was obtained from the “MARISCAL” market in Puyo city, and it was transported for 5 min to the UEA microbiology laboratory. The washing was immediately carried out and cut with a hammer mill, equipped with a blade and a 2-cm sieve. For lab analysis, two samples of natural rachis of 1 kg were collected. The remaining material was used for producing the silage, combining chopped rachis (67 %), wheat powder (20 %), Pecutrin (0.5 %), molasses (2 %), calcium carbonate (0.5%) and whey (10 %). As experimental units, a control (natural rachis) and 18 microsilos of 1 kg capacity were used, which were evaluated on days 0, 1, 4, 8, 15 and 30. Three microsilos were used for each day of conservation.
The pH check was made to the 18 microsilos on days 0, 1, 4, 8, 15 and 30 of being ensiled. For determining pH, an aqueous extract was used, consisting of a fraction of 25 g of silage and 250 mL of distilled water.
Crude protein (CP) was determined in the samples of natural and ensiled rachis by Kjeldahl methodology. Total phenol determination in gallic acid equivalent (GAE) was carried out by Folin-Ciocalteau method, and antioxidant activity (TROLOX) according to ABTS 2.2 azinobis (3-ethylbenzothiazolin-6-sulfonic acid). All analyzes were performed by triplicate in the UEA bromatology laboratory.
Organoleptic characteristics, such as smell (sweet, mild acid and strong acid), color (light brown, yellowish brown, mahogany brown, oxidized brown and dark brown) and consistency (solid, semi-solid and liquid) were assessed in all microsilos, in different experimentation days. Analysis of variance was performed and Duncan (1955) test (P <0.05) was applied. All analyzes were processed using Infostat statistical program, version 2012 for Windows.
Table 1 shows results of pH, CP, total phenols and antioxidant activity of natural and ensiled banana rachis. The pH showed the highest (P <0.05) value on day zero, and partially decreased until day four. Between days eight, 15 and 30, it was stable, with no differences. The highest CP values were obtained in the ensiled rachis on days eight, 15 and 30, without significant differences among them. These values were higher (P <0.05) than those of ensiled rachis on days one, four and zero, in natural state. Regarding the content of total phenols, it presented the highest value on day 30, while the lowest was obtained for rachis in its natural state. Regarding antioxidant activity, the best value was evident on day eight of fermentation, while the lowest value corresponded to natural rachis.
Table 1 Performance of pH, crude protein, total phenols and antioxidant activity of banana rachis in ensiled and natural state
abcdefgDifferent letters in the line show differences at the level of P<0.05, according to Duncan (1955)
The pH is one of the main parameters that can affect fermentation of ensiled food. In addition, it is closely related to microbial growth and phytochemical structural changes that occur during fermentation. The highest pH was obtained between days zero and one, which is due to the low acidification of the medium (Borrás-Sandoval et al. 2017). However, from day four of evaluation and until day 30, an ideal pH was obtained for silage conservation. This is due to the action of lactic bacteria present in the substrate. These microorganisms transform soluble carbohydrates into lactic acid, and manage to reduce the pH rapidly until stabilizing it (Aguirre et al. 2018).
Protein increase of the ensiled material, with respect to rachis in natural state, is due to the unicellular protein (bacteria, yeasts and filamentous fungi) developed during this process. Microbial protein is nutritionally similar to fish and soy bean protein. In studies of protein content and amino acid profile of the unicellular protein of Kluyveromyces marxianus, Candida utilis and Sacharomyces cerevisiae, high crude protein contents have been reported (42.19, 49 and 45 %), and levels of lysine, threonine, arginine, valine and leucine are highlighted (Gutiérrez and Gómez 2008 and Páez et al. 2008).
The greatest increase in the content of polyphenols in the ensiled rachis is related to LAB starter culture used in silos (Nisa et al. 2019). During fermentation, microorganisms synthesize enzymes (β-glucosidase, α-amylase, laccase, and some others) that can break ester bonds and release phenolic acids. In this way, it improves nutraceutical potential of food and increases the bioavailability of free phenolic acids (Acosta-Estrada et al. 2014).
The highest antioxidant activity was obtained in fermented rachis. LAB have the capacity of breaking ester compound bonds into free phenolic compounds. Nisa et al. (2019) fermented rice bran with 10 % of L. lactic and L. plantarum inocula, and obtained double antioxidant activity, regarding bran in natural state. The effect of LAB on antioxidant activity could be explained by the release of simple phenolic compounds after acid and enzymatic hydrolysis of phenolic compounds, polymerized during fermentation. In fact, enzymes function within substratum and activate free hydroxyl groups in phenolic structure. As a consequence, antioxidant activity of the substratum is increased by the presence of free phenolic content (Bhanja et al. 2009).
Regarding the organoleptic characteristics of silage, on days zero and one, it presented a sweet smell, and on days four, eight, 15 and 30, the smell was mild acid. During the study days, a light brown color and solid consistency were obtained. The change in smell during conservation days is due to the acidification process of the medium (Caicedo et al. 2019).
It is concluded that, through fermentation of orito banana rachis, improvements were achieved in crude protein content, total phenols and antioxidant activity, which makes it possible to obtain a functional food that can be used for feeding animals.
