Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
J Stored Prod Res ; 99: 102024, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36466545

RESUMEN

Smallholder farmers in Bangladesh often use low-density polyethylene (LDPE) bags contained within woven polypropylene bags to store wheat seed during the summer monsoon that precedes winter season planting. High humidity and temperature during this period can encourage increased seed moisture and pests, thereby lowering seed quality. Following a farm household survey conducted to inform trial design, eighty farmers were engaged in an action research process in which they participated in designing and conducting trials comparing traditional and alternative seed storage methods over 30 weeks. Factorial treatments included comparison of hermetic SuperGrainbags® (Premium RZ) against LDPE bags, both with and without the addition of dried neem tree leaves (Azadirachta indica). SuperGrainbags® were more effective in maintaining seed moisture at acceptable levels close to pre-storage conditions than LDPE bags. Both seed germination and seedling coleoptile length were significantly greater in hermetic than LDPE bags. Neem had no effect on seed moisture, germination, or coleoptile length. SuperGrainbags® were also more effective in abating seed damage during storage, although inclusion of neem within LDPE bags also had significant damage. Quantification of seed predating insects and diseases suggested that SuperGrainbags® also suppressed Coleopteran pests and blackspot, the latter indicative of Fusarium graminearum. Conversely, where farmers used LDPE bags, neem also had an additional though limited pest suppressive effect. Post-storage treatment scoring by farmers revealed a strong preference for SuperGrainbags® and no preference differences for or against neem. This study demonstrates a process by which farmers can be involved in the participatory co-design and testing of alternative wheat storage options, and stresses the need to develop SuperGrainbag® supply chains so hermetic storage can be made widely available.

2.
Bull Entomol Res ; 111(4): 499-510, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33766166

RESUMEN

The performance of six grain storage technologies for the control of insect pests in maize was evaluated over a 36-week (9-month) storage period. The six technologies used were: two ZeroFly® hermetic bag brands (laminated and non-laminated); Purdue Improved Crop Storage (PICS) bag; non-hermetic ZeroFly® bag; woven polypropylene (PP) bag containing maize grain treated with Actellic Gold® Dust (pirimiphos-methyl 1.6% + thiamethoxam 0.3%) and woven PP bag containing untreated grain. Each bag was filled with 50 kg maize grain and four replicates of each were set up. With the exception of the non-hermetic ZeroFly® bag, 50 live adults of the larger grain borer Prostephanus truncatus and of the maize weevil Sitophilus zeamais, were introduced into all the bags. Insects were not introduced into the non-hermetic ZeroFly® bag to assess its effectiveness in repelling infestation from outside. Parameters recorded were gas composition (oxygen and carbon dioxide) levels inside the bags; weight of flour generated by insect feeding activities; grain moisture level; live adult insect counts; grain damage and weight loss; grain germination rate and aflatoxin level. At termination, the plastic liners of the hermetic bags were examined for perforations. Results show that oxygen depletion and carbon dioxide evolution were faster in ZeroFly® hermetic compared to PICS bags. Throughout the 36-week storage trial, grain damage remained below 4% and weight loss below 3% in all the treatments except in the untreated PP bags in which it increased to 81.1 and 25.5%, respectively. The hermetic PICS, ZeroFly® and Actellic Gold dust-treated PP bags maintained grain germination at 60%, which was lower than the initial 90%, while in untreated control, it reduced to 4.7%. The mean aflatoxin levels fluctuated between 0.39 and 3.56 parts per billion (ppb) during 24 weeks of storage in all the technologies tested, which is below the acceptable maximum level of 10 ppb in maize. Based on the evaluation results, it can be concluded that hermetic PICS and ZeroFly® bags and woven PP bag with Actellic Gold dust-treated grain effectively protected stored maize grain from insect attack and weight losses. Appropriate strategies and mechanisms for the effective and efficient adoption of hermetic storage bag technology at scale would contribute towards global food security.


Asunto(s)
Aflatoxinas/análisis , Almacenamiento de Alimentos/instrumentación , Control de Insectos/instrumentación , Gorgojos , Zea mays , Animales , Parasitología de Alimentos , Germinación , Insecticidas , Compuestos Organotiofosforados , Tiametoxam , Zea mays/química , Zea mays/fisiología
3.
Food Policy ; 85: 64-71, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31217660

RESUMEN

We use an incentive compatible experimental auction to measure demand for a new agricultural technology, a triple layered hermetic storage bag. When used properly, the bag creates an airtight seal that reduces storage loss from insect pests and neutralizes aflatoxin contamination in stored grain. We find that demand for this new technology is highly elastic (4.3) and that the wholesaler could increase profit by lowering the price. We also find that farmers' valuation for the bag is not significantly different based on the medium through which information about it is communicated to them, either text, audio or video messages. This suggests that practitioners should use the cheapest option for disseminating information, which is text messaging in this context. In addition, we find that farmers who have prior awareness of the bag are willing to pay 20% more on average than those previously unaware of it. In total, the highly elastic demand for the improved bags, along with the fact that prior awareness of the bag leads to higher willingness to pay, suggests that a one-time price subsidy for the new technology could spur demand and increase future adoption.

4.
J Stored Prod Res ; 77: 106-111, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29899581

RESUMEN

Purdue Improved Crop Storage (PICS) bags were designed to reduce grain storage losses on smallholder farms. The bag consists of three layers: two high-density polyethylene liners fitted inside a woven polypropylene bag. Recently, farmer groups, development relief programs, and government food security agencies have shown interest in PICS bags for large-scale use. PICS bags are conventionally closed by a twist-tie (TT) method, which involves twisting, folding, and tying the lip of each layer individually with a cord. This is not only time and labor intensive, but also may affect the integrity of the liners. We evaluated three new bag closure methods: i) inner liner rolled onto itself and middle liner fold-tied (IR), ii) both liners folded together and tied (FT), and iii) both liners folded and tied separately (FS), along with the conventional twist tie (TT) method. The time to close partially or fully filled 50 kg-capacity PICS bags filled with maize grain was assessed. Results showed that FT was the most time-saving method, reducing bag sealing time by >34% versus the usual TT method. The average internal oxygen levels reached <2% within a week in bags containing grain highly infested with Sitophilus zeamais, while it remained >5% levels for less-infested bags. In both cases, insect population growth was suppressed. Oxygen depletion rates among tying methods remained the same regardless of the closure method used. When large numbers of bags need to be closed, the time-saving FT method is a good alternative PICS sealing method over the conventional twist-tie approach.

5.
J Food Sci Technol ; 55(4): 1366-1375, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29606751

RESUMEN

This study reports on aflatoxin production and peanut (Bailey's variety) quality, for four peanut pre-storage treatments; [(Raw clean (Raw-Cl), Raw inoculated with Aspergillus flavus NRRL 3357 (Raw-Inf), inoculated partially roasted but not-blanched (PRN-blanch); and inoculated partially roasted, blanched with discolored nuts sorted out (PR-blanched)]. All four treated samples were packaged in four different packaging systems [polypropylene woven sacks (PS), hermetic packs (HP), hermetic packs with oxygen absorbers (HPO), and vacuumed hermetic packs (HPV)] and stored under controlled conditions at a temperature of 30 ± 1 °C and water activity of 0.85 ± 0.02, for 14 weeks. Raw-Inf samples in PS had a higher fungal growth with a mean value of 8.01 × 104 CFU/g, compared to the mean values of samples in hermetic packs: 1.07 × 103 CFU/g for HP, 14.55 CFU/g for HPO, and 57.82 CFU/g for HPV. Similarly, the hermetic bags were able to reduce aflatoxin level of the Raw-Inf samples by 50.6% (HP), 63.0% (HPV), and 66.8% (HPO). Partial roasting and blanching in PS also reduced aflatoxin level by about 74.6%. Quality maintenance was the best for peanuts in HPO, recording peroxide value (PV) of 10.16 meq/kg and p-Anisidine (p-Av) of 3.95 meq/kg compared to samples in polypropylene woven sacks which had PV of 19.25 meq/kg and p-Av of 6.48 meq/kg. These results indicate that using zero-oxygen hermetic packaging, instead of the conventional polypropylene woven sacks, helped to suppress aflatoxin production and quality deterioration. Also, partially roasted, blanched and sorted peanuts showed a potential for reducing aflatoxin presence during storage.

6.
J Stored Prod Res ; 72: 54-58, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28659647

RESUMEN

We conducted an experiment in Niger to evaluate the performance of hermetic triple layer (Purdue Improved Crop Storage- PICS) bags for the preservation of shelled and unshelled groundnut Arachis hypogaea L. Naturally-infested groundnut was stored in PICS bags and woven bags for 6.7 months. After storage, the average oxygen level in the PICS bags fell from 21% to 18% (v/v) and 21%-15% (v/v) for unshelled and shelled groundnut, respectively. Identified pests present in the stored groundnuts were Tribolium castaneum (Herbst), Corcyra cephalonica (Stainton) and Cryptolestes ferrugineus (Stephens). After 6.7 months of storage, in the woven bag, there was a large increase in the pest population accompanied by a weight loss of 8.2% for unshelled groundnuts and 28.7% for shelled groundnut. In PICS bags for both shelled and unshelled groundnuts, by contrast, the density of insect pests did not increase, there was no weight loss, and the germination rate was the same compared to that recorded at the beginning of the experiment. Storing shelled groundnuts in PICS bags is the most cost-effective way as it increases the quantity of grain stored.

7.
J Stored Prod Res ; 69: 65-71, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27990031

RESUMEN

Postharvest insect pests threaten the nutritional and financial security of smallholder farmers in the developing world. Hermetic storage, a technology that protects grain against insects by blocking their supply of oxygen, alleviates the problem of insect-caused losses. PICS (Purdue Improved Crop Storage) bags represent one hermetic technology that improves food availability and incomes of farmers. The polyethylene liners of PICS bags are sometime damaged during use, acquiring small holes or tears. Observations in the laboratory and field suggest that insect development remains localized around the point where the bag is damaged. We hypothesized that the grain within a hermetic container that has minimal localized damage (such as an insect hole), helps retard leakage of oxygen into the bag and contributes to limiting insect damage and to the overall protective effect. To test this hypothesis, we filled 4 cm dia. by 10 cm long PVC pipes with Callosobruchus maculatus (F.) infested cowpeas and sealed them with caps having a single, insect-sized hole in its center. A vertical tube positioned above the cowpea-filled PVC pipe was filled with one of three different grains (sesame, sorghum, and maize) to different depths (0, 5, 15, 30, 50 cm). Seed size and grain barrier depth significantly reduced the level of bruchid damage to the stored cowpea in the PVC container. Smaller sized grains used for the barriers retarded insect development more effectively than larger sized grains, while deeper grain depth was more effective than shallower barriers. The grain held in a hermetic container contributes in a small, but significant, way to the effectiveness of the containers.

8.
J Econ Entomol ; 108(5): 2479-88, 2015 10.
Artículo en Inglés | MEDLINE | ID: mdl-26453738

RESUMEN

Fumigated dry common beans (Phaseolus vulgaris L.) that were artificially infested with Acanthoscelides obtectus Say, and others that were not artificially infested, were stored in hermetic triple-layer PICS (Lela Agro, Kano, Nigeria) or woven polypropylene (PP) bags for 6 mo at ambient laboratory temperature conditions of 22.6 ± 1.9°C and 60.1 ± 4.3% relative humidity. In an additional trial, beans contained in PP bags were treated with Actellic Super dust before introducing A. obtectus. Moisture content, number of live adult A. obtectus, seed damage, weight loss, and seed germination were determined at monthly intervals. At 6 mo, beans stored in PICS bags retained higher moisture than those stored in PP bags, but in all treatments the moisture level remained below that recommended for safe storage of beans. In the PICS bags, proliferation of A. obtectus did not proceed and at 6 mo, beans stored in these bags did not have insect-inflicted seed damage or weight loss. In contrast, seed damage and weight loss in PP bags exceeded economic threshold after 1 mo in the absence of Actellic Super dust (Syngenta Crop protection AG, Basle, Switzerland), and after 2 mo in the presence of it. Germination of beans stored in PP bags decreased greatly whereas the beans stored in PICS bags did not show reduced germination. Chemical free storage of common beans in PICS bags protects them against damage by A. obtectus.


Asunto(s)
Escarabajos/fisiología , Almacenamiento de Alimentos/métodos , Control de Insectos/métodos , Phaseolus , Animales , Almacenamiento de Alimentos/instrumentación , Herbivoria , Control de Insectos/instrumentación , Nigeria , Semillas
9.
Insects ; 14(12)2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38132627

RESUMEN

Millions of smallholder farmers use airtight (hermetic) storage to preserve stored commodities. However, relying on biological agents (i.e., insects) to deplete residual oxygen in airtight containers can occasionally extend the process, potentially resulting in grain damage or nutrient loss. Current oxygen scavengers used to remove this residual oxygen are unavailable and unsuitable on smallholder farms in developing countries. We evaluated the effectiveness of germinating seeds for oxygen depletion. Treatments comprised 10, 20, and 30 germinating cowpea seeds in 2 L jars filled with infested cowpea grains. Insect mortality and grain quality were assessed after 24, 48, 72, 96, and 120 h. Progeny development was monitored for 49 days post-treatment. The results showed that all germinating seeds depleted oxygen to 5% or below within 48 h. Complete adult mortality was achieved after 72 h for both 20 and 30 germinating seeds and 120 h for 10 germinating seeds. As germinating seeds increased, egg counts decreased. No adults emerged post-treatment after insects were exposed for 96 and 120 h to hypoxia from 30 and 20 germinating seeds, respectively. However, 120 h insect exposure to hypoxia from 10 germinating seeds had negligible progeny development. Moisture content increased slightly in grains exposed to 30 germinating seeds. Germinating seeds are as effective as controlled atmospheres in accelerating insect deaths, but further research is needed for field application and their effects on stored product quality.

10.
3 Biotech ; 13(2): 64, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36718411

RESUMEN

The storage of food grains against the fungal infection has been a great challenge to the farmers, but nanotechnology provides a solution to address this problem. The application of nanotechnology for the storage of food grains replaces synthetic fungicides in agriculture. Inorganic nanoparticles such as silver and zinc oxide are well-known for their antifungal activity. Green synthesized nanoparticles show enhanced antimicrobial activity than the chemically synthesized nanoparticles. Extracts and essential oils derived from plants exhibit very good antifungal properties. The synthesized nanoparticles can be impregnated in packaging materials, which are used to store food grains. Natural materials are having advantages like non-toxicity and easier to degrade and are suitable for food safety. This overview discusses the nanomaterials-mediated protection of food materials from mycotoxin and its releases into the open environment.

11.
Food Chem ; 373(Pt B): 131020, 2022 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-34774381

RESUMEN

Peanuts are transported by ship from production regions to all across the globe. Quality problems are frequently encountered due to increased levels of free fatty acids (FFAs) and a decline in organoleptic quality through lipid oxidation occurring during transport and storage. We studied the role of moisture (water activity, aw) in interaction with 87 days hermetic storage under air or nitrogen gas. Upon storage with air, some lipid oxidation was observed at water activity levels below 0.73. FFA levels increased at water activity levels above 0.73 and fungi proliferated at water activities above 0.80. Lipid oxidation, an increase in FFA levels and fungal growth were not observed after storage under nitrogen gas. It can be concluded that peanut storage and transport under anoxia can strongly reduce quality losses.


Asunto(s)
Arachis , Agua , Hongos , Humedad
12.
Heliyon ; 7(10): e08235, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34754976

RESUMEN

Storage is an important aspect of food security in developing countries. Therefore, it is crucial for farmers to have access to sustainable storage technologies to cope with storage losses. Maize is an important staple and commercial food in Rwanda, but maize farmers are still being challenged by storage losses because of the lack of proper storage facilities. It is in that regard that advanced maize storage technology, notably hermetic maize storage technology, has been introduced in Rwanda in 2012. However, since its introduction, the adoption rate is low among smallholder maize farmers. Understanding the factors influencing farmers' choice of alternative maize storage technology could provide Rwandan policymakers with important information for designing policies and programs aimed at reducing maize post-harvest losses to enhance household food security. This study used a multivariate probit model on a randomly selected cross-sectional sample of 301 smallholder maize farmers from the Gatsibo District of Rwanda to take part. The results revealed that the common maize storage technologies used among smallholder farmers were polypropylene sacks with and without chemicals, hermetic bags, and silos. Only 41% of respondents used hermetic maize storage technology. The model results showed that membership in a farmer group, access to credit, the quantity of maize produced, access to training, and selling maize soon after it dries, were the major factors influencing the decision of smallholder farmers to use alternative maize storage technologies. The study recommends that the policymakers and other stakeholders in post-harvest loss reduction should support the dissemination of advanced storage technologies to facilitate access. The government should support farmer acquisition of post-harvest maize loss reduction technologies either through subsidization of hermetic bags or provision of cheap credit.

13.
Food Res Int ; 147: 110483, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34399479

RESUMEN

This study aimed to evaluate the effects of low oxygen partial pressure (pO2) and high carbon dioxide partial pressure (pCO2) combined with different temperatures on the oil acidity and peroxide values of two soybean cultivars (NA 5909 RG and FEPAGRO 37 RR). The volatile compounds correlated to lipid oxidation were also evaluated. Soybeans were stored for seven months under ambient and controlled atmosphere (CA) conditions at three temperatures (20, 25, and 30 °C). Storage under ambient conditions increased acidity and peroxide value regardless of the temperature. CA storage with low pO2 reduced oil acidity and its combination with high pCO2 had no positive effects on oil acidity and peroxide values. Grains of FEPAGRO 37 RR stored under ambient air showed higher 1-octne-3-ol amount compared to CA. The higher storage temperature increased (E)-2-heptenal and decanal amount in grains of cultivar NA 5909 RG. In addition, the ambiente air storage provide higher γ-Butyrolactone in relation to CA storage. Moreover, in both cultivars the CA storage technique provides lower (E)-2-hexenal content. This compound, together with hexanal are potential lipid deterioration markers of soybeans. CA storage is a promising tool for soybean grains preservation and the effect is mainly due to the oxygen reduction, with no additional effect of CO2 increasing.


Asunto(s)
Atmósfera , Glycine max , Lípidos , Oxidación-Reducción , Temperatura
14.
Glob Food Sec ; 28: 100468, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36568028

RESUMEN

Millions of smallholder farmers in low-income countries are highly vulnerable to food-supply shocks, and reducing this vulnerability remains challenging in view of climatic changes. Restrictions to limit the spread of the COVID-19 pandemic produced a severe supply-side shock in rural areas of Sub-Saharan Africa, including through frictions in agricultural markets. We use a large-scale field experiment to examine the effects of improved on-farm storage on household food security during COVID-19 restrictions. Based on text message survey data we find that the prevalence of food insecurity increased in control group households during COVID-19 restrictions (coinciding with the agricultural lean season). In treatment households, equipped with an improved on-farm storage technology and training in its use, food insecurity was lower during COVID-19 restrictions. This underscores the benefits of improved on-farm storage for mitigating vulnerability to food-supply shocks. These insights are relevant for the larger, long-term question of climate change adaptation, and also regarding trade-offs between public health protection and food security.

15.
Insects ; 11(8)2020 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-32824419

RESUMEN

Several postharvest technologies are currently being commercialized to help smallholder farmers in sub-Saharan Africa reduce grain storage losses. We carried out a study in Northern Benin to compare the effectiveness of five technologies being sold to protect stored grain. Maize that had been naturally infested by insects was stored in four hermetic storage technologies (SuperGrainbag™, AgroZ® bag, EVAL™, and Purdue Improved Crop Storage-PICS™ bags), an insecticide impregnated bag (ZeroFly®), and a regular polypropylene (PP) woven bag as control. Oxygen levels in hermetic bags fluctuated between 0.5 ± 0.0 (v/v) and 1.0 ± 0.3 (v/v) percent during the seven months of storage. No weight loss or insect damage was observed in grain stored in any of the hermetic storage bags after seven months. However, grain stored in ZeroFly® and PP woven bags had weight losses of 6.3% and 10.3%, respectively. These results will help farmers and development agencies when making decisions to use and/or promote storage technologies to reduce postharvest grain losses.

16.
Environ Sci Pollut Res Int ; 27(33): 42064-42071, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32705556

RESUMEN

Storage of wheat in conventional packaging materials is not safe as seeds gain moisture from surrounding air of high relative humidity which promotes growth of fungal and insect pests and loss of quality during storage. Implementing the dry chain, initial drying to low moisture content followed by storage in hermetic bags to maintain low moisture may prevent these losses without using fumigants or chemicals. Different levels of initial moisture contents (SMC), i.e., 8, 10, 12, and 14% and packaging materials, including hermetic super bags along with paper, woven polypropylene (PP), jute, and cloth bags were used as two factors for this experiment. After 4 months of storage, small variation in SMC of seed was observed in super bags while SMC increased significantly in conventional packaging materials. Higher storage losses (≈9%), grain quality losses and aflatoxin B1, B2, G1, and G2 contamination (1-2 ppb) in conventional packaging materials were linked to high seed moisture contents. Storage in hermetic bags at 8 and 10% SMC ideally preserved seed quality. In conclusion, hermetic storage of wheat at low seed moisture maintains a dry chain and prevents aflatoxin contamination and grain quality losses and offers an organic approach to avoid contamination of food grains.


Asunto(s)
Aflatoxinas , Plaguicidas , Aflatoxinas/análisis , Grano Comestible/química , Semillas/química , Triticum
17.
J Econ Entomol ; 112(4): 1989-1996, 2019 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-31086959

RESUMEN

Modified atmospheres such as hermetic storage are widely used for the control of stored grain insect pests. To improve their effectiveness, there is need to better understand insect responses to low-oxygen environments. Adult Callosobruchus maculatus F. (Coleoptera: Chrysomelidae: Bruchinae) on cowpea and Sitophilus oryzae L. (Coleoptera: Curculionidae) on wheat were exposed to hypoxia treatments consisting of 1, 3, and 5% oxygen levels for 14 d. Acoustic activity was monitored during the experiment, and insect mortality and grain quality were examined immediately after the hypoxia treatments. Adult emergence was assessed 45 d post-treatment. All three hypoxia treatments eliminated acoustic activity of both species within 4 d. There was neither insect survival for both species nor significant grain damage immediately after 14-d exposure to hypoxia treatments. No adult insects emerged 45 d post-exposure on grains maintained at 1% oxygen level for 14 d. However, at 3 and 5% oxygen levels, there were eggs on cowpea, holes in wheat, and emerging adults for both insect species 45 d post-exposure. Although insect activity ceased within 4 d when hypoxia was maintained below 5%, there is need to explore exposure beyond 14 d for 3 and 5% oxygen levels, to ensure to avoid potential adult emergence from eggs and other insect life stages post-treatments. Maintaining 3-5% hypoxia conditions for a longer duration would ensure insufficient oxygen is available for progeny development.


Asunto(s)
Escarabajos , Gorgojos , Acústica , Animales , Grano Comestible , Hipoxia
18.
J Econ Entomol ; 110(6): 2707-2715, 2017 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-29045682

RESUMEN

Hermetic storage is of interest to farmers and warehouse managers as a method to control insect pests in small storage facilities. To develop improved understanding of effects of hermetic storage on insect pest activity and mortality over time, oxygen levels, acoustic signals, and observations of visual movement were recorded from replicates of 25, 50, and 100 adult Sitophilus oryzae (L.) (Coleoptera: Curculionidae) hermetically sealed in 500- and 1,000-ml glass jars. Recordings were done for 28 d; twice daily for the first 6 d and twice weekly thereafter. Insect sounds were analyzed as short bursts (trains) of impulses with spectra that matched average spectra (profiles) of previously verified insect sound impulses. Oxygen consumption was highest in treatments of 100 insects/500-ml jar and lowest in 25/1000-ml jars. The rates of bursts per insect, number of impulses per burst, and rates of burst impulses per insect decreased as the residual oxygen levels decreased in each treatment. Activity rates <0.02 bursts s-1, the acoustic detection threshold, typically occurred as oxygen fell below 5%. Mortality was observed at 2% levels. The time to obtain these levels of insect activity and oxygen depletion ranged from 3-14 d depending on initial infestation levels. Acoustic detection made it possible to estimate the duration required for reduction of insect activity to levels resulting in negligible damage to the stored product under hermetic conditions. Such information is of value to farmers and warehouse managers attempting to reduce pest damage in stored crops.


Asunto(s)
Comunicación Animal , Almacenamiento de Alimentos , Control de Insectos/métodos , Oxígeno/análisis , Gorgojos/fisiología , Acústica , Animales , Almacenamiento de Alimentos/métodos , Densidad de Población , Dinámica Poblacional
19.
Food Chem ; 232: 60-66, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-28490117

RESUMEN

Orange maize is being promoted as a source of provitamin A carotenoids (pVAC) in Zambia. Carotenoid retention in orange maize grains stored in metal silos, multilayer polyethylene and common woven bags, and maize meal packaged in single and multilayer polyethylene bags was evaluated. Significant differences in total pVAC retention were found between grain storage methods (48.1-57.2%) after 6months of storage. Total pVAC retention in hammer meal (73.1-73.5%) was higher than in breakfast meal (64.3-69.3%) after 4months of storage; however, no differences in pVAC retention were found between meal types when stored in single and multilayer polyethylene bags. In general, ß-cryptoxanthin (ßCX) had higher retention than ß-carotene (ßC). Potential contribution of stored orange maize to the estimated average requirement of children and women was 26.5% and 24.3%, respectively. Orange maize meal can provide significant amounts of provitamin A to diets of Zambians even after 4months of storage.


Asunto(s)
Zea mays , Carotenoides , Grano Comestible , Femenino , Embalaje de Alimentos/métodos , Almacenamiento de Alimentos/métodos , Humanos , Zambia , beta Caroteno
20.
Foods ; 6(1)2017 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-28231087

RESUMEN

While fulfilling the food demand of an increasing population remains a major global concern, more than one-third of food is lost or wasted in postharvest operations. Reducing the postharvest losses, especially in developing countries, could be a sustainable solution to increase food availability, reduce pressure on natural resources, eliminate hunger and improve farmers' livelihoods. Cereal grains are the basis of staple food in most of the developing nations, and account for the maximum postharvest losses on a calorific basis among all agricultural commodities. As much as 50%-60% cereal grains can be lost during the storage stage due only to the lack of technical inefficiency. Use of scientific storage methods can reduce these losses to as low as 1%-2%. This paper provides a comprehensive literature review of the grain postharvest losses in developing countries, the status and causes of storage losses and discusses the technological interventions to reduce these losses. The basics of hermetic storage, various technology options, and their effectiveness on several crops in different localities are discussed in detail.

SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda