Nanoscopic Characterization of Starch Biofilms Extracted from the Andean Tubers Ullucus tuberosus, Tropaeolum tuberosum, Oxalis tuberosa, and Solanum tuberosum.

The replacement of synthetic polymers by starch biofilms entails a significant potentiality. They are non-toxic materials, biodegradable, and relatively easy to gather from several sources. However, various applications may require physicochemical properties that might prevent the use of some types of starch biofilms. Causes should be explored at the nanoscale. Here we present an atomic force microscopy surface analysis of starch biofilms extracted from the Andean tubers melloco (Ullucus tuberosus), mashua (Tropaeolum tuberosum), oca (Oxalis tuberosa), and potato (Solanum tuberosum) and relate the results to the macroscopic effects of moisture content, water activity, total soluble matter, water vapor permeability, elastic properties, opacity and IR absorption. Characterization reveals important differences at the nanoscale between the starch-based biofilms examined. Comparison permitted correlating macroscopic properties observed to the topography and tapping phase contrast segregation at the nanoscale. For instance, those samples presenting granular topography and disconnected phases at the nanoscale are associated with less elastic strength and more water molecule affinity. As an application example, we propose using the starch biofilms developed as a matrix to dispose of mouthwash and discover that melloco films are quite appropriate for this purpose.

Effects of Gaseous Ozone on Microbiological Quality of Andean Blackberries (Rubus glaucus Benth).

Andean blackberries are highly perishable due to their susceptibility to water loss, softening, mechanical injuries, and postharvest diseases. In this study, the antimicrobial efficacy of gaseous ozone against spoilage (mesophiles, psychrotrophs, and yeasts and molds) and pathogenic (E. coli, S. enterica, and B. cinerea) microorganisms was evaluated during 10 days of storage at 6 ± 1 °C. Respiration rate and mass loss were also determined. Ozone was applied prior to storage at 0.4, 0.5, 0.6, and 0.7 ppm, for 3 min. The best results were observed with the higher ozone dose, with initial maximum reductions of ~0.5, 1.09, and 0.46 log units for E. coli, S. enterica, and B. cinerea, respectively. For the native microflora, maximum reductions of 1.85, 1.89, and 2.24 log units were achieved on day 1 for the mesophiles, psychrotrophs, and yeasts and molds, respectively, and this effect was maintained throughout storage. In addition, the lower respiration rate and mass loss of the blackberries ozonated at 0.7 ppm indicate that this treatment did not induce physiological damage to the fruit. Gaseous O3 could be effective in maintaining the postharvest quality of blackberries throughout refrigerated storage but higher doses could be advisable to enhance its antimicrobial activity.

Green Banana (Musa acuminata AAA) Wastes to Develop an Edible Film for Food Applications.

In this study, edible packaging based on discarded green banana (Musa acuminata AAA) flour (whole banana and banana peel flours) was developed for food applications. Films were characterized in terms of film-forming ability, mechanical, barrier, thermal, microbiological, and sensory properties. The film forming solutions were studied for rheological properties. Two formulations were selected based on their film-forming ability: whole banana flour (2.5%), peel flour (1.5%) and glycerol (1.0 %, F-1.0 G or 1.5%, F-1.5 G). Adding 1.5% plasticizer, due to the hygroscopic effect, favored the water retention of the films, increasing the density, which also resulted in a decrease in lightness and transparency. Water activity shows no difference between the two formulations, which were water resistant for at least 25 h. DSC results showed a similar melting temperature (Tm) for both films, around 122 °C. Both films solutions showed a viscoelastic behavior in the frequency spectrum, being the elastic modulus greater in F-1.0 G film than F-1.5 G film at low frequency. F-1.0 G film was less firm, deformable and elastic, with a less compact structure and a rougher surface as confirmed by AFM, favoring a higher water vapor permeability with respect to F.1.5 G film. Microorganisms such as Enterobacteria and Staphylococcus aureus were not found in the films after a period of storage (1 year under ambient conditions). The F-1.0 G film with added spices (cumin, oregano, garlic, onion, pepper, and nutmeg) was tested for some food applications: as a snack (with or without heat treatment) and as a wrap for grilled chicken. The performance of the seasoned film during chilled storage of chicken breast was also studied. Sensory evaluation showed good overall acceptability of all applications. In addition, the chicken breast wrapped with the seasoned film registered lower counts (1-log cycle) than the control (covered with a polystyrene bag) and the film without spices. Green banana flour is a promising material to develop edible films for food applications.

Influence of Underutilized Unripe Banana (Cavendish) Flour in the Formulation of Healthier Chorizo.

The purpose of this work was to obtain chorizos by partially fat replacing with banana flour (whole or peeled). These chorizos were formulated with 3% pork fat and 24% whole banana flour (BC) or banana peel flour (BPC). A third formulation of chorizo with 15% pork fat and 12% wheat flour (WC) was also produced for comparison. Cooking loss was 12.5% for the WC, while for the BC and BPC chorizos it was 7.2% and 6.9%, respectively. All three products had similar water, protein, and ash contents, whereas carbohydrate and fiber contents were the main changes in composition. The color of the three different formulations did not change markedly, but an increase in yellowness and chromaticity was observed in the BC chorizo, as well as a slight decrease in lightness and in the whiteness index in the BPC one. Textural properties declined from day 0; from day 3 onwards, they remained constant in all chorizos and properties, except for BC lot in cohesiveness. Mesophilic aerobic bacteria, as well as mold and yeast counts, were predominantly high in the WC during chilled storage. Moreover, the sensory analysis indicated high acceptability of the formulated with wheat or whole banana flour, although those with banana peel flour scored slightly lower. This study shows that incorporating banana flours into the formulation successfully reduced the incorporation of pork back-fat, resulting in excellent quality sensorial characteristics due to the technological parameters and sensory acceptance.

Underutilized Green Banana (Musa acuminata AAA) Flours to Develop Fiber Enriched Frankfurter-Type Sausages.

This study aimed to develop a fiber-enriched Frankfurter-type sausage by incorporating underutilized green banana flours as a meat extender, replacing wheat flour with banana flours (8%). A low-fat formulation substituting 12% pork fat with 24% banana peel flour was also studied. Sausages were stored at 4 °C/15 days. Cooking loss was low (5.6-4.1%) in all formulations and the substitution of wheat flour with banana flour did not modify moisture and protein composition, while carbohydrate, fiber, and ashes varied with the flour composition. In the low-fat sausages, fiber carbohydrate and ashes increased the most. Texture and color parameters were very similar for high-fat sausages throughout storage, although low-fat sausage showed higher hardness, while chewiness, L*, and whiteness tended to decrease. During the first week of storage, the microbial growth was scarce and then, an increase, except in the low-fat batch, in which growth remained constant. Enterobacteria and Staphylococcus aureus were not detected during storage. Sensory attributes throughout storage were very similar for all high-fat sausages; the odor in the formulations was defined as "different" but not unpleasant. The low-fat sausages, defined as a new product different from conventional sausages, were well accepted by the panelist. Banana flours are a suitable ingredient option to add nutritional value to Frankfurter-type sausages, which can be consumed by the wheat allergic population.