Ricardo Enrique Bartosik

Soybean expeller (SBE), a by-product of soybean oil extraction through the extruding-expelling process, is widely used as a protein source in animal feed and soy-based foods. This study evaluated fungal contamination and mycotoxin levels in SBE samples from 11 extruding-expelling facilities in Argentina, assessing fungal load, moisture content (MC), and mycotoxin profiles. Fungal biota was quantified through colony forming unit (CFU) counts and identified via morphological analysis, while mycotoxins were quantified using liquid chromatography and tandem mass spectrometry. CFU counts were low (0 to 4 CFU g⁻¹ DM), with Penicillium spp. (28.0%) and Mucoraceae (family) (25.6%) being the most frequently isolated genera. Deoxynivalenol (DON) and aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂) were detected in 20% to 40% of the samples. The average concentration was 215.19 µg kg⁻¹ for DON and 41.68, 0.39, and 0.34 µg kg⁻¹ for AFB₁, AFG₁, and AFG₂, respectively. Although most mycotoxin concentrations were below regulatory limits, a few samples exceeded the threshold for DON (8.6%) and AFB₁ (2.9%). Co-occurrence of two mycotoxins was observed in 60% of the samples. These results highlight the importance of monitoring fungal contamination and mycotoxin levels to ensure the safety and quality of SBE for feed and food applications.

Seed quality declines during storage depending on relative humidity, temperature, and oxygen concentration. Low-oxygen atmospheres significantly enhanced the germination and vigor of seeds during storage in laboratory-scale experiments. Low-oxygen atmospheres include self-modified atmospheres, where gas composition changes due to microbial respiration and oxidative processes, as well as modified atmospheres, where gas composition is initially altered from an external source without further adjustments. However, the potential of low-oxygen atmospheres to preserve the quality of maize (Zea mays) seeds in bags of 25–50 kg capacity, like those employed by seed companies and small-scale farmers, remains underexplored, hindering a broader adoption of this storage technology. Our study assessed the feasibility of applying low-oxygen atmospheres for seed storage on the pilot scale, i.e., hermetic containers of 25 kg capacity made of polyethylene and polyamide, under controlled conditions. We first evaluated the ability of the hermetic containers to maintain low oxygen levels over time. Then, we compared the germination and vigor of seeds stored in the hermetic containers under modified and self-modified atmospheres with those stored in traditional poly-paper bags under normal atmospheric conditions. The seeds had 14% moisture content (wet basis) and were stored at 25 °C and 10 °C. Maintaining low oxygen levels in polyethylene–polyamide bags was feasible. Moreover, at 25 °C, modified and self-modified atmospheres maintained higher germination values (95.8% and 94.4%, respectively) compared to traditional storage (68.3%), and both were as effective as refrigeration (97.6%). However, refrigeration was better for preserving seed vigor, with radicle emergence values of 85.2% in self-modified atmospheres and 78.9% in modified atmospheres, compared to 65.0% and 61.2%, respectively, at 25 °C. In conclusion, the advantages of modified atmospheres observed in laboratory-scale studies are achievable on a larger scale with a proper container design, advancing the prospects for the practical application of this technology for the seed industry and small farmers.

Over the past two decades, the silo bag system has gained popularity for storing grains and by-products under hermetic conditions. However, the impact of higher temperatures in the outer grain layer on key industrial parameters, such as wheat baking quality, remains insufficiently understood. Traditional silo bags are black on the inside and white on the outside to reflect sunlight, but colored bags, recently introduced to the market, absorb more heat, potentially warming the grain and causing damage. This study aimed to assess the effect of grain strata and bag color on grain temperature and quality under field conditions. Results showed a significant surface temperature increase in colored bags compared to white ones, approximately 3 °C, which affected the temperature of the peripheral grain layer. Moisture content slightly increased (0.2 percentage points) in the outer grain layer. However, many industrial quality parameters (protein content, P/L, W, and loaf volume) and the germination test for wheat, showed no significant differences between colored and white bags or between different strata after 120 days of storage, although the falling number increased and wet gluten decreased. These findings suggest that, despite surface temperature differences, the overall industrial quality of wheat remains unaffected by external bag coloration. The influence of ambient temperature on the peripheral layer was estimated to affect approximately 5–10% of the grain mass, indicating that adverse impacts on grain quality may go unnoticed without implementing stratified sampling techniques.

Soybean seeds (Glycine max) were dried under real scale conditions to different final moisture content (m.c.) (9.1, 9.7, 10.9 %, and control with 16.2 %) and processed through extruding-expelling. Results indicated that soybean seed m.c. affected the composition of the soybean expeller and, thus, the oil extraction efficiency (OEE), which increased as the seed m.c. decreased. A polynomic model was proposed for predicting OEE as a function of soybean m.c., indicating that drying soybean to 10 % resulted in an OEE of approximately 65 %. A thin layer drying experiment of soybean seeds indicated that the protein dispersibility index (PDI) was not affected as regards drying air temperatures up to approximately 69 °C, and a bi-linear model with a non-pre-established break point was fitted. The real scale drying treatment in a rack type dryer (mixed flow) did not show any effect (p > 0.05) on the PDI at 80 °C, while at 115 °C a reduction (p < 0.05) was observed (PDI reduction was 0.8 and 2.1 percentage points, respectively).