Storage Of Maize Grains Research Articles

Storage Losses of Maize in Four Different Storage Methods in Thangrong Gewog, Mongar Dzongkhag

Several maize storage technologies are made available and recommended to the farmers in the villages by different agencies to reduce post-harvest losses. This study aimed to evaluate the storage losses of maize mainly to insect and fungal damages in four different storage methods for a maximum of five months storage period in Thangrong, Mongar dzongkhag (district). Freshly harvested maize was shelled, dried, weighed and stored under four different storage methods and replicated three times for each storage method. Moisture content, physiological weight loss, insect and fungal damages were the storage quality parameters assessed monthly until five months of storage. All the storage methods maintained the moisture content within the range recommended for the safe storage of maize (12-14 %). The physiological loss of weight (PLW) was the lowest at 0.10 % for the maize grain stored in super bag and the highest at 0.30 % was observed in grains stored in curing and storage shed over the four-month storage period. Traditional storage and silos resulted in PLW of 0.20 % and 0.16 %, respectively. Overall insect damage (sum for five months) of 2.54 % in the traditional storage was the highest reported among the storage methods followed by 1.79 % for grains stored in curing and storage sheds. Insect damage of 0.64 % for super bag and 0.27 % for silo stored maize grains were observed. Fungal damaged grain ranged from a low of 0.19 % for curing and storage shed to a high of 0.31 % for super bag stored maize grains. Overall storage losses (sum for five months) to insects and fungal diseases were in the range of 0.51-2.80 % with the highest being observed in traditional storage and the lowest in silo storage. All the storage methods evaluated maintained good quality maize grains with minimal damage till five months of storage. The existing improved storage technologies could help in the safe storage of maize grains if stored after proper drying. It is recommended to conduct a similar comparative study for the maize harvested and stored in the summer months and also at a different location to validate the results.

Hedonic Sensory Quality of Maize Grains Conserved by A Triple Bagging and Biopesticides System (Leaves of Lippia multiflora Moldenke and Hyptis suaveolens Poit)

In Côte d'Ivoire, inefficient storage Practices which can be dangerous to consumers' safety and to the environment are hampering the widespread availability of cereals, especially maize. Thus, a triple bagged system with or without plant biopesticides (Lippia multiflora and Hyptis suaveolens leaves) was used in this study to determine its effectiveness in preserving the hedonic sensory qualities of the grains for a period of 18 months under a 3-factor central composite design (CCD). The first CCD factor consisted of 6 observation periods: 0; 1; 4.5; 9.5; 14.5 and 18 months. The second factor was the type of treatment, which included a control lot with a polypropylene bag (NT) and 9 experimental lots, one of which was triple bagged without biopesticides (MGT1 and the other eight (8) lots containing varying proportions and/or combinations of biopesticides (MGT2 to MGT9). Finally, the third factor concerned the combination of the two biopesticides with the percentage (%) of Lippia multiflora as reference. Treated and stored maize kernels were periodically removed and processed into porridge for sensory analysis using a 9-point hedonic scale. The sensory parameters studied were color, taste, aroma, smell, mouthfeel and overall acceptability. The results showed that storage of maize grains in a triple bagging and biopesticide system for up to 18 months did not affect the hedonic sensory attributes studied. The porridges made from these grains were therefore judged pleasant by the panelists throughout the storage period. On the other hand, the porridges produced from grains stored in a polypropylene bag (NT) were considered unpalatable by the panelists after only 4.5 months of storage with respect to these sensory parameters evaluated. The results of the PCA and CAH analysis showed that the incorporation of at a minimum of 1.01% biopesticides (Lippia multiflora and Hyptis suaveolens leaves) in the triple bagging systems made the conservation better and maintained the organoleptic properties of the maize grains throughout the 18-month period.

INFLUENCE OF DIFFERENT DRYING TECHNIQUES ON PHYSIOCHEMICAL AND NUTRITIONAL QUALITY OF MAIZE (Zea mays) GRAIN

Objectives: This study attempt to investigate the appropriate drying methods for post-harvest storage of maize grains with preserving important quality and physiochemical characteristics. Methods: The maize samples were dried using different drying methods such as field drying, greenhouse drying, solar drying, direct fire drying, hot air drying, and forced air drying. Further, the dried maize grains were analyzed for physical parameters of bulk density, particle density, porosity, specific gravity, shrinkage, and color. The proximate composition of dried maize grains was analyzed for crude protein, fiber, fat content, moisture, and ash content. Results: There were significant differences (p<0.05) observed for bulk density, particle density, porosity, specific gravity, shrinkage, and color between different drying techniques. When considering proximate analysis, protein, moisture, and ash content were shown significant differences (p<0.05) between different drying methods. Whereas, fat and fiber content of samples were not shown a significant difference (p>0.05) for different drying methods. Conclusion: Different drying methods affect the quality and physiochemical properties of maize grains. Among different drying techniques, the forced air oven drying method preserved physiochemical and nutritional properties considerably compared to other drying techniques.

Evolution of Mycotoxins during Maize Grains Storage in Triple Bags Containing Plants Biopesticides (Lippia multiflora and Hyptis suaveolens)

In Côte d’Ivoire, maize plays an essential role as subsistence, commercial and socio-cultural culture. To consume good quality corn, it is necessary to preserve the sanitary quality through a good storage method. The aim of study was to evaluate sanitary quality of stored maize in triple bags containing plants biopesticides. Maize grains were collected in March 2016 in the north of Côte d’Ivoire. The fresh leaves of Lippia multiflora and Hyptis suaveolens were collected and dried in sunlight for 7 days in the center of Côte d'Ivoire. Triple bags were bought in Abidjan market. All this material was sent to the Laboratory of Biochemistry and Food Sciences, Félix Houphouët-Boigny University, Côte d’Ivoire, to perform the experiment. A central composite design was used for sample constitution. Ten treatments were obtained for the experimentation. The first treatment was conservation of 50 kg of maize grain in a polypropylene bag. The second treatment was conservation of 50 kg of maize grain in a triple bag. The other eight treatments were carried out with PICS bags each containing 50 kg of maize grain and different proportions of chopped leaves Lippia multiflora and Hyptis suaveolens. Thus, a control group with polypropylene bag (TPPB0), a control group in triple bag without biopesticides (TPB0) and 8 experimental lots of triple bags noted TB1 containing 0.625kg L. multiflora and 0.625kg H. suaveolens, TB2 with 0.40 kg of L. multiflora and 1.60 kg of H. suaveolens, TB3 with 1.60 kg of L. multiflora and 0.40 kg of H. suaveolens, TB4 with 0.10 kg of L. multiflora and 0.40 kg of H. suaveolens, TB5 with 0.40 kg of L. multiflora and 0.10 kg of H. suaveolens, TB6 with 2.5 kg of L. multiflora and 2.5 kg of H. suaveolens, TB7 with 1.25 kg of L. multiflora and TB8 with 1.25 kg of H. suaveolens have been used. The contents of moisture, water activity, aflatoxin B1 (AFB1), ochratoxin A (OTA), fuminosin B1 (FB1) and zearalenone (ZEA) were studied. The levels of AFB1, OTA, FB1 and ZEA resulted from maize grains treated with biopesticides were significantly lower than those recorded with untreated maize of control bags. The results show AFB1 levels (from 4.17 ± 0.05 to 5.15 ± 0.06 μg/kg), OTA levels (from to 4.58 ± 0.25 to 6.10 ± 0.01 μg/kg), FB1 levels (from 4.96 ± 0.07 μg/kg to 7.42 ± 0.06 μg/kg) and ZEA levels (from 4.66 ± 0.10 μg/kg to 8.78 ± 0.14 μg/kg). Maize samples stored in triple bagged bags with different proportions of biopesticide were significantly lower than those recorded in the polypropylene woven sample bag (TPPB0) and in the triple bagged control bag (TPB0) during the storage period. Storage of maize grains in triple bags with the leaves of L. multiflora and H. suaveolens appears as a method of effective and inexpensive conservation to ensure the sanitary quality of maize. This inexpensive and easy-to-use treatment should be popularized among farmers.

Evolution of Merchantability during Storage of Maize Triple Bagged Containing Biopesticides (Lippia multiflora and Hyptis suaveolens)

The aim of study was to evaluate merchantability quality of stored maize in triple bagging with biopesticides. Maize grains were collected in March 2016 in the north of Côte d’Ivoire. The fresh leaves of Lippia multiflora and Hyptis suaveolens were collected and dried in sunlight for 7 days in the center of Cote d'Ivoire. Triple bags were bought in Abidjan market. All this material was sent to the Laboratory of Biochemistry and Food Sciences, Félix Houphouët-Boigny University, Côte d’Ivoire, to perform the experiment. Ten treatments were obtained for the experimentation. The first treatment was conservation of 50 kg of maize grain in a polypropylene bag. The second treatment was conservation of 50 kg of maize grain in a PICS bag. The other eight treatments were carried out with PICS bags each containing 50 kg of maize grain and different proportions of chopped leaves Lippia multiflora and Hyptis suaveolens. A central composite design was used for sample constitution. Thus, a control group with polypropylene bags (TPPB0), a control group in PICS bags without biopesticides (TPB0) and 8 experimental lots of triple bags noted TB1 containing 0.625 kg L. multiflora and 0.625 kg H. suaveolens, TB2 with 0.40 kg of L. multiflora and 1.60 kg of H. suaveolens, TB3 with 1.60 kg of L. multiflora and 0.40 kg of H. suaveolens, TB4 with 0.10 kg of L. multiflora and 0.40 kg of H. suaveolens, TB5 with 0.40 kg of L. multiflora and 0.10 kg of H. suaveolens, TB6 with 2.5 kg of L. multiflora and 2.5 kg of H. suaveolens, TB7 with 1.25 kg of L. multiflora and TB8 with 1.25 kg of H. suaveolens have been used. Changes in moisture, damages and weight losses were studied. The results show moisture levels (from 09.02±0.11% to 12.07± 0.06%), weight loss (from 0.49±0.02% to 2.54±0.07%) and damage (from 0.99±0.02% to 3.96± 0.01%), corn stored in triple bagged bags with different proportions of biopesticide were significantly lower than those recorded in the Polypropylene woven sample bag (TPPB0) and in the triple bagged control bag during the storage period. The results obtained indicate stability in the quality of maize stored for 18 months in triple bagged bags containing different proportions of leaves of L. multiflora and H. suaveolens. A proportion of 5% of the mixture of leaves of L. multiflora and H. suaveolens (2.5 kg of L. multiflora and 2.5 kg of H. suaveolens) in triple bagged bags is recommended for a better preservation of the merchantability of the stored maize grains kernels.
 Storage of maize grains in PICS bags with the leaves of L. multiflora and H. suaveolens appears as a method of effective and inexpensive conservation to ensure the merchantability quality of maize.

Germination Energy and Capacity of Maize Seeds Following Low-Temperature Short Storage

The present research attempts to characterize the effect of low temperatures, and the moisture content of maize (Kosmo 230) meant for sowing on its energy and capacity to germinate. Seeds were moistened to varying degrees and stored under various conditions; then, their germination energy and capacity were assessed. Sowing material with 15% moisture content showed slightly declined germination ability when stored at −25–−20 °C for over three days, while the storage of seeds with a 25 and 30% moisture content at −5–0 °C for 1–3 days had the effect of seed conditioning. Seedlings obtained from conditioned seeds showed sustainability characterized by faster growth, and demonstrated nearly twice the size as other plants. Warehousing and storage of maize grains with a 11.12% moisture content at temperatures up to −25 °C did not significantly affect seed germination capacity or energy, irrespective of storage time.

An insecticide formulation of terpene ketones against Sitophilus zeamais and its incorporation into low density polyethylene films

The use of active natural compounds derived from plants appears as an interesting alternative for pest control in stored products. In this study, the fumigant toxicity of several terpene ketones against maize weevil (Sitophilus zeamais) adults was assessed, and the effect of their combination with piperonyl butoxide (PBO), a cytochrome P450 inhibitor commonly used as synergistic agent, was investigated. A mixture of the most active ketones (R-(+)-pulegone and thymoquinone) was then tested on S. zeamais, and finally this mixture was incorporated into low density polyethylene (LDPE) films by supercritical CO2 impregnation, in order to study the fumigant toxicity of this formulation against S. zeamais under laboratory conditions, as well as the release profile of the active ketones. PBO showed antagonistic effects in combination with terpene ketones, decreasing the toxicity of the individual compounds and therefore increasing their lethal concentrations. The mixture of ketones showed a lower lethal concentration (LC50 value of 7.12 μL/L air) than the individual compounds, thus indicating a synergistic effect between them. Finally, the impregnated films revealed high toxicity values (up to 95% mortality), and maintained a moderate level of activity even after 8 days of exposure. In conclusion, the mixture of these active terpene ketones incorporated into a polyethylene film, material commonly used for hermetic storage of maize grains, could be applied as a potential technology against insect pests.

Sorption isotherms of agricultural products

The aim of the paper is to expand the theory of sorption and equilibrium moisture contents as well as to present the methodology of developing two types of sorption isotherms – I and II. The attention is also paid to the importance of the isotherms in the thermodynamics of drying and in the process of storage of agricultural products. Presented methodology of obtaining the isotherms is based on selected equations of the theory of adsorption and on the results of experimental measurements of equilibrium moisture content. Definition of the new isotherm II is introduced as dependence of equilibrium moisture content dry basis on time at constant temperature, constant relative moisture of the ambient air and stable biological properties (e.g. germination). The results show following graphic dependences: isothermal distort plane; sorption isotherm I of maize grains at various temperatures; moisture loss rate in dependence on time and sorption isotherm II. These theoretical dependences supported by experimental measurements broaden the scope of the theory of sorption and may be successfully applied in long-term storage of maize grains.

Essential oil of Ocotea odorifera: An alternative against Sitophilus zeamais

AbstractNowadays, the maize weevil Sitophilus zeamais—Motsch 1855 is the most relevant pest found during storage of maize grains. Aiming at protecting the agricultural crops, high amounts of synthetic pesticides are used around the world. In this sense, this work aimed at evaluating the insecticidal and repellent effect of essential oil of Ocotea odorifera (Vellozo) Rohwer (Lauraceae) (O. odorifera (sassafras)) leaves against the maize weevil in maize grains. The essential oil's chemical composition showed that sassafras contains camphor (43%) and safrole (42%) as major compounds. Our results show that sassafras oil was insecticidal and repellent to maize weevil. About 100% mortality was achieved using a concentration of 0.32 μl cm−2, after 24 h of exposure. The LD50 value was 14.1 μl or 0.09 μl cm−2 and the study of the effect on insect mortality at the lethal doses (LD50) showed that after 72 h mortality was 100%. The values of the preference index varied from −0.39 (0.065 μl cm−2) to −0.63 (0.659 μl cm−2), demonstrating that the plant oil presents repellent activity. The repellency bioassay simulating small bins showed the repellent effect level from 0.64 (0.36 μl cm−3) to 0.94 (2.9 μl cm−3). The essential oil of sassafras presented insecticidal and repellency against maize weevil. Although from an economical point of view synthetic chemicals are still more frequently used as repellents, natural products (essential oils) have the potential to provide efficient and safer repellents for humans and the environment.

Resfriamento artificial na conservação da qualidade comercial de grãos de milho armazenados

O resfriamento artificial é uma ferramenta para conservação da qualidade de grãos nas regiões tropicais. Este trabalho foi realizado com o propósito de verificar o efeito da refrigeração artificial do ar, por meio de aeração, na preservação da qualidade de grãos de milho em armazém graneleiro horizontal, de fundo "V". Para o experimento foram utilizados dois septos, sendo um resfriado artificialmente (12ºC), com capacidade de 28 mil toneladas, e o outro aerado com ar natural, com capacidade de 29 mil toneladas. As amostragens foram realizadas, em ambos os septos, durante a carga, aos 60 e 120 dias após a primeira etapa de resfriamento e durante a expedição dos grãos. Durante o armazenamento, as amostragens foram realizadas considerando-se a posição e a profundidade da massa de grãos de milho. A avaliação qualitativa consistiu na determinação dos seguintes parâmetros: peso de mil grãos, temperatura da massa de grãos, teor e acidez de óleo, identificação de fungos, teor de aflatoxina, índice de infestação de insetos e porcentagem de grãos infestados. O resfriamento artificial promoveu a diminuição da temperatura da massa de grãos, independentemente das condições de temperatura e umidade do ar externo. A aeração artificial, com ar frio, preservou os parâmetros atribuídos à qualidade dos grãos e proporcionou redução na percentagem de grãos infestados e na população de insetos-praga na massa do produto. Assim, a utilização do resfriamento artificial no armazenamento de grãos de milho em regiões tropicais é eficaz na manutenção da qualidade dos grãos e no manejo de insetos e patógenos.

Nutritional changes in maize ( Zea mays) during storage at three temperatures

Nutritional changes in maize grains stored at 10, 25 and 45 °C for 6 months were studied. Significant decrease in pH and increase in titratable acidity was observed during storage of maize grains at 25 and 45 °C. Moisture contents of maize grains decreased by 25% at 25 °C and 38% at 45 °C after six months of storage. Total soluble sugars increased by 10.7% at 10 °C and 17.3% at 25 °C, whereas a 39.5% decrease was observed after 6 months storage at 45 °C. Total available lysine and thiamine contents in maize grains decreased by 13 and 9.26% at 25 °C, 16 and 20.4% at 45 °C, respectively, after 6 months of storage. Protein digestibility decreased by 5.19 and 9.0% at 25 and 45 °C, respectively, whereas decrease in starch digestibility was 9.86% at 25 °C and 15.1% at 45 °C on storage of maize grains for 6 months. However, no significant nutritional changes occurred during storage of maize grains at 10 °C.