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.

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.

The changes in oxygen (O2) and carbon dioxide (CO2) concentrations were characterized during the hermetic storage of barley seeds (Hordeum vulgare L.) in glass jars at different temperatures (5, 15, 25, and 35 degrees C) and moisture content levels (12%, 14%, and 16%). Gas concentration curves were analyzed using both linear and non-linear models to describe the trends. The respiration rate was determined for each temperature and moisture content combination as storage time advanced and O2 was consumed. The performance of the models was assessed using an independent dataset. The values of respiration rates obtained in this study were from -0.1103 to -56.0336 mg O2/(kgDM d) and from 0.0136 to 71.8876 mg CO2/(kgDM d), and accumulated dry matter loss was computed based on these respiration rates. Our study confirms that the respiration of barley seeds is greatly influenced by the aw conditions. Respiration rates of the seeds are negligible when the aw falls below 0.7. However, as the aw surpasses this threshold, respiration rates gradually increase due to microbial activity. Temperature also exerts a significant influence on the respiration rate of barley seeds. Furthermore, as the aw conditions increase, the respiratory quotient also increases, approaching a value of 1 as the aw approaches 0.7. These findings provide valuable information for understanding the dynamic of respiration and optimizing storage conditions to maintain barley seed quality during long-term storage.

Silo-bags (grain bag, sausage bag or silo bolsa) have been used for storing grains in Argentina for more than 25 years, and are now fully integrated in the grain postharvest system at different levels with important economic and logistic benefits for the agricultural sector. Additionally, silo-bags are being adopted in more than fifty countries, from the tropics to the cold regions of the world. Given the interest that silo-bag technology is arousing worldwide, it is timely to review the state of the art and identify gaps in scientific knowledge. The scope of this review includes the particular ecosystem of the grain stored in silo-bags, the abiotic components (temperature, moisture content and gasses) and interactions with biotic components (microorganisms and insects), alternatives for insect control treatments, effect of storage conditions on grain quality, modelling work, and the impact of the silo-bag system on the economics and logistics of the agricultural sector. Additionally, gaps in knowledge that need to be addressed in future research projects are identified and discussed.

Shea nuts are a nutritionally and economically important tree crop harvested seasonally in rural areas of sub-Saharan Africa. Storage losses are a major constraint in the shea nut value chain, with substantial amounts lost prior to processing and marketing. Hermetic bags have proven to be a viable technology for the effective storage of grains, oilseeds and pulses in sub-Saharan Africa due to their efficacy, low cost, and commercial availability. However, hermetic bag storage technology has not been investigated for the preservation of shea nut quality. In this study, shea nut storage in hermetic bags was compared to storage in jute sacks and woven polypropylene (PP) bags. Shea nuts had an initial moisture content of 7.3% (w.b.) and insect damage of 28%. Each storage treatment consisted of 12 bags of 20 kg shea nuts with samples taken from 3 bags every 6 weeks over a 30-week storage period. As ambient temperature and relative humidity conditions varied over time, moisture content varied within 1 percentage point in hermetic bags compared to 3 percentage points in the jute sacks and PP bags. Insect damage was maintained below 30% in hermetic bags, compared to 80% and 82% in PP bags and jute sacks, respectively. Weight loss due to insect damage was 4.5% in the hermetic bags compared to 10.1% and 11.6% in the jute sacks and PP bags, respectively. Carbon dioxide concentration in the hermetic bags remained below 6% over 30 weeks, indicating low insect and microbial activity. The results of this study have proven hermetic bag storage technology to be a viable option for the quality preservation of dry shea nuts, which should be strongly considered for adoption in the shea nut value chain.

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).

Understanding microbial development under the typical storage conditions of maize seeds is crucial for maintaining seed quality and ensuring successful crop establishment. In this study, the respiration and microbial growth of yellow-dent maize seeds stored at 12%, 13%, and 14% moisture content (corresponding to 65%, 70%, and 75% relative humidity, respectively) and 25 degrees C were investigated. Two maize seed lots (hybrids KM4500 and KM4580) with different initial fungal loads were used in the experiments. To calculate the respiration rates, seeds were stored in hermetically closed jars and the oxygen and carbon dioxide concentrations were monitored for 180 days. The microbial load (colony forming units and percentage of infected seeds) was measured prior and after storage at the three humidity levels. At 65% and 70% relative humidity, respiration rates were close to zero in both seed lots, indicating minimal microbial activity. However, at 75% relative humidity, respiration rates showed a bell-shaped pattern, suggesting the onset of microbial activity in both seed lots. The seed lot with higher initial fungal load (KM4500) presented a higher respiration rate. The microbial load decreased at 65% and 70% relative humidity and the decreasing trend reverted at 75% relative humidity. This work indicates that 70% relative humidity is a safe storage moisture to prevent microbial activity at 25 degrees C in the studied yellow-dent maize seeds, independently of their initial fungal load. Hermetic storage, also, would make sense for seed storage only above 75% r.h. (14% m.c.) This study provides valuable insight for preserving seed quality during long-term commercial storage.

Low oxygen atmospheres have proven to be effective to protect seed quality in many species during storage. In maize, however, the evidence is ambiguous since positive, negative, and neutral effects were reported. These apparent contradictions might relate to the different experimental conditions explored in previous studies (i.e., combinations of oxygen concentration, relative humidity, and temperature). The aim of this work was to study the effect of anoxic atmospheres (< 1% oxygen) on germination and vigor of maize seeds stored under five combinations of relative humidity and temperature (65%, 75%, and 85% relative humidity at 25 & DEG;C, and 65% relative humidity at 30 & DEG;C and 35 & DEG;C) under strict control of experimental conditions. Data of germination and radicle emergence (vigor) were analyzed using Generalized Linear Models. Our results show that the effect of anoxia on seed quality depends on relative humidity and temperature. At 25 & DEG;C, anoxia benefited both germination and vigor at 75% and 85% relative humidity compared to the normal atmosphere, while at 65% relative humidity the benefit was only detectable on vigor. Additionally, the benefit of anoxia on germination was higher at a relative humidity of 85% than at 75%. At 30 & DEG;C and 35 & DEG;C and 65% relative humidity, anoxia was neutral to seed germination and vigor. Anoxia, in conclusion, benefits seed quality under particular combinations of relative humidity and temperature usually found in real storage conditions. This turns anoxic storage in a potential technology to extend the shelf life of maize seeds for both small-farmers and seed companies.

Se evaluó el efecto de distintos tratamientos de secado (natural, 50 y 70 °C) y manejo agronómico (sin y con re-fertilización en pre-floración) sobre la dureza endospérmica en cuatro híbridos de maíz (AW 190, NK 940, Cóndor y Mill 522). La dureza se evaluó mediante peso hectolítrico (PH), test de flotación (TF) en NaNO3 y CCl4 y relación de molienda (RM). El ensayo se basó en un diseño factorial. Generalmente, altos valores de PH y RM y bajos de TF están asociados con maíces más duros. Se observó que el secado artificial (50 y 70 °C) disminuyó RM, aumentó TF y no produjo mayores cambios en PH, disminuyendo así la dureza. Los híbridos Cóndor (secado natural) y con re-fertilización (secado a 50 °C), Mill 522 (secado natural y a 50 °C) y en el manejo control (secado a 70 °C) lograron valores de dureza para calidad ‘Premium’. Las técnicas empleadas permitieron clasificar los híbridos por su dureza y evaluar el efecto de la temperatura de secado sobre la misma.

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus flavus may infect this crop at growing stage and the harvested kernels can be contaminated with aflatoxins (AFs), whose levels may increase during storage. In Argentina, silo bags, a hermetic type of storage system, are widely used. Biocontrol based on competitive exclusion by atoxigenic A. flavus strains is a useful tool for AFs management at pre-harvest stage. The aim of the present study was to evaluate the effect of pre-harvest biocontrol treatments on aflatoxin B1 (AFB1) accumulation in maize stored in silo bags during 3 and 6 months. Three bioformulations based on A. flavus AFCHG2 and ARG5/30 strains were applied during field trials as single and mixed inocula. Harvested kernels were stored in non-hermetic and hermetic silo bags. At initial time (t0), 3 and 6 months (t3 and t6) the following parameters were evaluated: percentage of damaged kernels, moisture content, water activity, Aspergillus section Flavi incidence, relative humidity, O2 and CO2 levels into the silo bags, and AFB1 levels. The biocontrol strains included in the 3 bioformulations were able to infect maize kernels during the field trial and displaced native toxigenic isolates. At t0 control plots showed 10.9 ± 0.4 μg/kg of AFB1 while no AFs were detected in all the treatments. Along the storage assay AFB1 levels varied from not detected (<1 μg/kg) to 20.1 ± 0.8 μg/kg. Hermetic bags were better than non-hermetic bags in preventing AFB1 accumulation. Both single and mixed inocula were effective to control AFB1 accumulation in maize kernels during 3 and 6 months. AFB1 was not detected in kernels from the treatment at field stage with AFCHG2 + ARG5/30 after 6 months of storage into hermetic bags. The application of the biocontrol agents at field stage is an appropriate tool to reduce AFB1 accumulation under storage in hermetic silo bags. This is the first report on biocontrol strategy based on native atoxigenic strains applied at pre-harvest stage to reduce AFB1 accumulation during storage in Argentina.

Respiration of biotic components of the grain ecosystem generates self-modified atmospheres (oxygen reduced and carbon dioxide enriched) during hermetic storage. The effect of temperature, moisture content and modified atmospheres on the evolution of maize microbiota is not entirely known. In this study, corn grain samples were conditioned to different moisture contents (14.3, 16.5 and 18.4%) and hermetically stored in glass jars at 15, 25 and 35 degrees C. Grain samples were collected at different stages of modified atmosphere evolution of each experiment: T0 (O-2: 21% initial concentration); T1 (O-2: 10%); T-2 (O-2: 0%); T3 (CO2 maximum concentration stabilized). Microbiota was quantified with Petri dish counts using selective growth media for different microbial groups. Additionally, ethanol, acetic acid and lactic acid were measured for monitoring anaerobic activity. Results indicated that there was a high correlation between water activity (aw) and the time to reach anaerobiosis (R-2 of 0.85), the maximum CO2 concentration (R-2 of 0.86), and the reduction of filamentous fungi and bacterial counts during hermetic storage (R-2 of 0.72 and 0.48, respectively). A differential behavior of the hermetic storage was observed according to aw of the grain, and a general conceptual model is offered for its understanding. It was concluded that modified atmospheres reduced or inhibited microbial growth in stored corn, and that aw was the most influential factor in the time to reach anaerobiosis, maximum CO2 concentration, and the filamentous fungi and bacterial counts reduction during hermetic storage. (C) 2021 Elsevier Ltd. All rights reserved.

The dynamics of oxygen (O-2) and carbon dioxide (CO2) concentrations were characterized in corn (Zea mays L.) seed hermetically stored in glass jars at 15, 25 and 35 degrees C and 14.3, 16.5 and 18.3% moisture content. Gas concentration curves were modeled with linear and exponential correlations and the respiration rate was calculated for each temperature and MC combination as storage time progressed and O-2 was consumed. Three predictive respiration models were proposed: Model I, dependent on temperature and MC, and Model IIA, dependent on temperature and oxygen (fitted for each MC level), and Model IIB, dependent on temperature, MC and O-2. All models were validated with two independent sets of experimental data. Respiration rate increased with MC and temperature, and it appeared that O-2 concentration affected respiration only after a critical limit of about 1% was reached. The values of respiration rates obtained in this study were from 1.36 to 823.76 mg O-2 kg(DM)(-1) d(-1) and from 0.83 to 1265.62 mg CO2 kg(DM)(-1) d(-1). Respiration rate substantially increased for a(w) conditions greater than 0.85, presumably due to the onset of the embryo's metabolic activity and the activation of the facultative microorganisms. Literature data was provided to support this observation. Based on this study, Models I and IIB could be indistinctly used in simulation models for predicting O-2 and CO2 evolution of hermetically stored seed. However, model IIB provides the advantage of attenuation of the respiration rate as O-2 is depleted. (C) 2021 IAgrE. Published by Elsevier Ltd. All rights reserved.

Pairs of soybean seeds and their correspondent expeller samples were collected from ten extrusion-expelling processing plants in Argentina. Seeds were analyzed for proximal composition, bulk moisture content (MC) and individual seed MC. Expeller were analyzed for proximal composition, bulk MC, protein solubility in KOH, expeller urease activity and free fatty acid content. Results indicated that average soybean composition was 136 g/kg MC, 207 g/kg oil and 391g/kg crude protein (CP), while the oil extraction efficiency (OEE) of the process was of 60.7%. The expeller composition was 922 g/kg dry matter (DM), 81g/kg oil and 442 g/kg CP. In soybean seeds, coefficient of variation (CV) of MC was 17.2%, 3.0% for CP and 5.1% for oil, while in SBE CV for DM was 2.9%, 3.9% for CP and 19.7% for oil. A relationship among soybean seed MC, OEE and expeller composition was found. Results of this work indicated that conditioning the soybean MC prior to processing is important not only to maximize OEE, but also to achieve uniform expeller composition and to assure anti-nutritional factors deactivation.

Soybean expeller (SBE) is rich in protein and has a relatively high and variable oil composition (7-15%). With the increasing use of the SBE for animal nutrition there arose a need for understanding the quality deterioration during storage. The goal of this research was to determine the storability of SBE by developing a model for predicting its equilibrium moisture content (EMC), using the EMC model to determine its safe storage moisture content (SSMC), and by measuring dry matter loss (DML) for SBE incubated at 10 degrees C and 20 degrees C for 46 days. Samples of SBE with different residual oil contents were collected and an EMC experiment was carried out to determine the sorption isotherms at 65, 70, 75 and 80% RH; at 10 and 20 degrees C for samples with 6.2, 9.6 and 15.3% oil content. A second set of samples was used for determining the respiration rate at 20 degrees C. The Enhanced Halsey model was fitted to the SBE EMC/equilibrium relative humidity (ERH) data and it was established that the residual oil content significantly affected the sorption isotherms. By considering an ERH of 67% or below to be a safe storage condition, the SBE should be stored at or below 12.2% moisture content (m.c.) if the temperature is at or below 20 degrees C and an the oil content is 7%. However, according to the respiration experiments it would be safe to store SBE up to 16% m.c. (equivalent to 75% ERH). Considering a DML limit of 0.1%, the allowable storage time of SBE at a m.c. lower than 15.4% (ERH of 75%) was at least 46 days. The widely accepted practice of incorporating the gums present in the extracted oil, diluted in water, back into the SBE should be avoided since it increases the m.c. of the product and substantially reduces the allowable storage time. (C) 2020 Elsevier Ltd. All rights reserved.

Silo bags have the potential to increase grain marketing efficiency and to give farmers additional bargaining power. However, silo bags are prone to tearing that can cause grain losses. This article assesses the economic outcomes of storing soybeans in silo bags, as compared to grain commercial storage facilities, considering the risk of grain losses. A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina. The soybean loss modelling is based on empirical measurements of silo bag losses. Results indicate that both silo bag and grain storage facility profits break-even, with 2% soybean losses. When soybean losses range between 0% and 5%, optimal storage time varies from 8.5 to 9.6 months, respectively. Results show that silo bag storage may not be optimal with 10% losses, and that a 3% price premium can compensate losses of up to 5%. Silo bags constitute a feasible storage alternative that can provided more flexibility to argentine agro industrial system in situations of limited storage capacity or of logistic problems. Highlights Silo bags have the potential to increase grain marketing efficiency, provide farmers with additional bargaining power and improve their economic results. Silo bags are prone to tearing that can cause grain losses. A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina. Silo bag and storage facility profits break-even with 2% soybean losses, and a price premium of 3% can compensate losses of up to 5%. Silo bags constitute a feasible storage alternative in situations of limited storage capacity or of logistic problems.

The rapid increase of the overall grain production of Argentina resulted with a storage capacity deficit in permanent structures of 40-50 million tons, and this context favored the rapid adoption of the silo bag technology. Silo bag allows differing grain selling from harvest time, taking advantage of the seasonal price changes and, hence, improving farmers' income. However, storing grain in silo bag could be risky if inadequate planning, handling or monitoring is implemented. Thus, the objective of this article was to develop a prediction model for soybean losses in silo bag storage based on monitoring CO2 concentration and other sensible variables. During 2013, an experiment was conducted in 13 soybean silo bags placed at farms and grain elevators in Balcarce area, South East of Buenos Aires province, Argentina, since May to December. Grain samples were collected and grain quality was evaluated. Storage variables, such as moisture content and interstitial atmosphere gas composition were also recorded, and at the end of storage, physical grain losses were quantified for each silo bag (kg of spoiled grain not commercialized). The results showed that there was not generalized quality loss in any silo bag, but localized losses were observed. These losses occurred due to water entrance in the silo bag through openings which resulted in spoiled grain from 140 to 4320 kg, representing from 0.07% to 2.16% in a 200 ton silo bag. Next, a correlation to predict grain losses was developed, which considered grain moisture and a predictor related to the CO2 concentration at the silo bag closing end as independent variables. This correlation explained 73% of the grain losses variability, allowed to model different levels of losses, and was consistent with biological concepts. (C) 2019 Elsevier Ltd. All rights reserved.

This is the first comprehensive study of the grain postharvest system of Argentina with the following objectives: 1) to group the grain elevators according to structural, technological, and insect control characteristics; 2) to analyze how the groups are positioned to take advantage of the expected increase in the country grain production; 3) to study how the different groups are positioned to adopt Best Management Practices (BMPs); and 4) to identify the main challenges of each group to implement Integrated Pest Management (IPM) programs under the new context of dichlorvos (DDVP) prohibition. A survey was conducted in 86 elevators in the main grain producing area of Argentina. Multiple correspondence and cluster analyses were used to study the relationships amongst the variables and to establish a typology of grain elevators. Three groups of facilities were identified, which mainly differed in size and grain reception capacity, turnover ratios, and fumigation modalities. Large and intermediate scale facilities emerged as the best positioned to profit the projected scenario of crop increase, because of their high reception capacity and their potential to increase the turnover ratios (these two groups handled 95% of the grain volume). Small elevators presented important constraints in their current equipment for grain reception. Large facilities appeared also as the best positioned to implement BMPs, because they would only require minor investments in aeration automation. Intermediate size facilities would also need to incorporate temperature cables for grain monitoring. BMP incorporation seems less feasible in small facilities, given the limitations in drying, aeration, and stored grain monitoring technologies. All the groups will have to make equal efforts to incorporate IPM programs after the banning of DDVP. The detection of group-specific constraints is expected to serve as an input for developing targeted technologies and more efficient sector policies.