6 research outputs found
Screening for antifungal activity of garlic (Allium sativum) powder against mycelia growth of three post-harvest pathogens
No full textScreening for antifungal activity of garlic powder against mycelia growth of three post-harvest pathogens (Aspergillus, Rhizopus and Mucor species) was investigated in this study. Five grams of malt extract agar (MEA) were poured into a conical flask, 100 ml of water and different weight of garlic powder (1, 3, 5 and 7 g) were separately added, stirred and later sterilized while MEA medium with no garlic added (0 g) served as control. The mycelia of each post-harvest pathogen was cut with 6mm cork borer and placed on the solidified medium in the Petri dish and incubated at 28±2oC for 72 hours. Phytochemical screening of the garlic powder was also investigated. Results from this study showed that the different weights of the garlic powder apart from the control (0 g garlic) significantly inhibited the mycelia growth of the three post-harvest pathogens tested in the study and the order of antifungal activity of the garlic powder against mycelia growth of Aspergillus, Rhizopus and Mucor species was 7 g > 5 g > 3 g > 1 g > 0 g, 5 g > 7 g >1 g > 3 g > 0 g and 7 g > 5 g > 3 g > 1 g > 0 g respectively. The antifungal activity of the garlic powder may be related to the presence of active antimicrobial agents including alkaloids, saponins, tannins, flavonoids and cardiac glycosides that were detected in the powder
Microorganisms Associated with the Deterioration of Fresh Leafy Indian Spinach in Storage
No full textEfficacy of cloves (Syzygium aromaticum) and ginger (Zingiber officinale) extracts against microbial spoilage of locally produced soymilk at ambient storage
No full textThere is a global concern at present with the use of synthetic chemical preservatives in foods due to carcinogenic and mutagenic related problems, resulting to the use of natural preservatives especially culinary herbs and spices in food products. Herein, efficacy of clove (Syzygium aromaticum) fruit and ginger (Zingiber officinale) rhizome was evaluated against rapid deterioration of locally produced soymilk at ambient storage by microorganisms and their bioactive compounds determined with gas chromatography and mass spectrometry (GC-MS). Interestingly, soymilk treated with 5% ginger extract among other tested concentrations had the least bacterial (2.00±0.50 ×104 cfu/ ml) and fungal (2.00±0.00 ×104 sfu/ml) counts that did not exceed the acceptable limit for pasteurized milk (3 ×104 cfu/ ml) by day 3 of storage when compared with untreated soymilk that recorded very high bacteria (56.50±6.50 ×104 cfu/ml) and fungi (13.50±1.50 ×104 sfu/ml) counts. The efficacy could be traced to beta-amyrin (24.15%), hexadecanoic acid (15.71%) and phytol (16.55%) that are major bioactive compounds detected in the ginger extract. Thus, the ginger extract offers prospect as promising alternative that can be applied in extending the shelf life of soymilk and other liquid processed foods.
DOI: http://dx.doi.org/10.5281/zenodo.1457231
Efficacy of cloves (Syzygium aromaticum) and ginger (Zingiber officinale) extracts against microbial spoilage of locally produced soymilk at ambient storage
No full textThere is a global concern at present with the use of synthetic chemical preservatives in foods due to carcinogenic and mutagenic related problems, resulting to the use of natural preservatives especially culinary herbs and spices in food products. Herein, efficacy of clove (Syzygium aromaticum) fruit and ginger (Zingiber officinale) rhizome was evaluated against rapid deterioration of locally produced soymilk at ambient storage by microorganisms and their bioactive compounds determined with gas chromatography and mass spectrometry (GC-MS). Interestingly, soymilk treated with 5% ginger extract among other tested concentrations had the least bacterial (2.00±0.50 ×104 cfu/ ml) and fungal (2.00±0.00 ×104 sfu/ml) counts that did not exceed the acceptable limit for pasteurized milk (3 ×104 cfu/ ml) by day 3 of storage when compared with untreated soymilk that recorded very high bacteria (56.50±6.50 ×104 cfu/ml) and fungi (13.50±1.50 ×104 sfu/ml) counts. The efficacy could be traced to beta-amyrin (24.15%), hexadecanoic acid (15.71%) and phytol (16.55%) that are major bioactive compounds detected in the ginger extract. Thus, the ginger extract offers prospect as promising alternative that can be applied in extending the shelf life of soymilk and other liquid processed foods.
DOI: http://dx.doi.org/10.5281/zenodo.1457231
Influence of gasoline emissions on tomato fruit rot by two fungi in tropical ambient conditions
No full textAbstract Background The release of pollutant gases into the atmosphere as a result of anthropogenic activities exert effect on biological systems at many levels. Combustion engines such as those in vehicles and power generators pollute the air with emissions from their exhausts. The gases released which are oxides of carbon, nitrogen; sulphur and particulate matter have effect on living things in the immediate environment. Up to 25% of harvested fruits and vegetables are lost mainly due to microbial activities before consumption. Disease development in ripe tomato fruit (host) by two of its fungal pathogens in the presence of generator emissions is presently being studied. Results Treatment produced variable effects depending on the fungus and the route of infection. For Rhizopus stolonifer coated and Fusarium oxysporum wound inoculated fruits, significant disease reduction was noticeable in the later days of storage, specifically from day 11. Fruits coated with F. oxsporum spores without wounding however, rotted more with gasoline emissions treatment also noticeably at the later period of storage. Long exposures caused greater rot reduction where disease was reduced and more severe rot where disease was enhanced. Rhizopus infected fruits were best preserved for 14 days by 40 min exposure while wound inoculated Fusarium infected fruits were best preserved by 45 min exposure. Disease reduction was 40–50% in both types of infection. Conversely, disease was most aggravated by about 50% by 45 min exposure of unwounded Fusarium infected fruits. Other exposures also caused increased rotting by about 5–35%. Conclusions The results demonstrate that air pollution by fumes from generators may under certain host–pathogen conditions be advantageous in prolonging postharvest life of ripe tomatoes, while at other times could be devastating when fruits are subsequently stored or marketed at tropical ambient temperature. The advantage, however, outweighs the negative effects
