15 research outputs found
A study of postharvest moisture loss in carrots (Daucus carota L.) during short term storage
No full textPostharvest moisture loss leads to wilting of horticultural produce which shortens their
shelf life and reduces their commercial value. Effects of preharvest water stress, potassium
(K), cultivar, water vapour pressure deficit (WVPD) and recharging (rehydration in water) on
postharvest moisture loss of carrots (Daucus carvta L.) during short term storage were studied.
In greenhouse experiments, carrots subjected to water stress for 4.5 weeks preceding
harvest had higher postharvest moisture loss, compared to unstressed carrots. Root water
potential followed by relative solute leakage (RSL), accounted for most of the variation
in moisture loss. It is suggested that preharvest water stress increases carrot tissue
permeability which enhances moisture loss.
Increase in K fertilization to 1.0 mM increased carrot size and lowered cell \\k and
osmotic potentials (ip^ and RSL from the root tissue. Regression analysis showed that K
affects moisture loss mainly by influencing carrot size and tissue permeability, and that the
benefit of K fertilization in improving shelf life is limited to conditions of low K availability.
Consistent differences in postharvest moisture loss among eight field-grown, late
harvested carrot cultivars were observed at low relative humidity. These differences, which
accounted for up to 6 days of difference in shelf life, were associated with specific surface
area and transpiration coefficient of carrot roots.
Carrots at high WVPD lost more moisture. The results showed carrot tissue
permeability increases during storage at high WVPD which further enhances the rate of
moisture loss. Increase in duration of recharging increased carrot weight gain but had no effect on
the rate of moisture loss during subsequent storage. Weight gain was greatest during the first
week after harvest. Recharging, therefore, should be explored as a means to replace moisture
lost and extend shelf life of carrots.
The effects of preharvest water stress, nutrition and cultivar on specific surface area,
\j4 and tissue permeability were found to be important in determining the shelf life of carrots,
It may be possible to improve the shelf life by reducing preharvest water stress, K
fertilization, cultivar selection, storage at high relative humidity, and recharging.Land and Food Systems, Faculty ofGraduat
Effect of Storage Temperature and Postharvest Tuber Treatment with Chemical and Biorational Inhibitors on Suppression of Sprouts During Potato Storage
No full textReplacement of Postharvest Moisture Loss by Recharging and Its Effect on Subsequent Moisture Loss during Short-term Storage of Carrots
No full textJournal articleReplacing postharvest moisture loss in carrots (Daucus carota L., `Caro-choice') by single and repeated recharging (rehydration in water) treatments, interaction between the duration of recharging and temperature during recharging, and the effects of these treatments on moisture loss during subsequent short-term storage were studied. Carrot mass gain increased with increase in duration of single recharging treatments. Carrots that had lost 2.96% of their mass during storage at 13 °C and 35% relative humidity regained as much as 83% of the mass during recharging for 12 hours. Longer rechargings had little additional effect. Recharging at 13 °C and 26 °C was more effective at replacing water than at 0 °C. The rate of moisture loss (percent per day) during subsequent storage was not affected by recharging duration and temperature during recharging. With repeated recharging every 3.5 days, increase in recharging duration up to 9 hours increased carrot mass gain. Most of the mass gain occurred following 0 to 7 days of storage. These treatments, however, did not affect the rate of moisture loss during subsequent storage. These results suggest that the beneficial effect of recharging on carrot quality is due to replacement of the lost moisture and not to a decrease in moisture loss during storage following recharging. Abrading increased mass loss in non-recharged carrots and increased mass gain during recharging. Recharging should be explored as an option to improve the shelf life of carrots
Effect of Packaging Material on Shelf Life and Quality of Ware Potato Tubers Stored at Ambient Tropical Temperatures
No full textSensory Attributes of Coffee under Different Shade Regimes and Levels of Management
No full textDespite coffee bean physical and beverage quality attributes being inherent factors, the environment, which includes crop management factors, can play a major role in determining their expression. This study was conducted to evaluate the effect of management and shade levels on beverage quality of coffee. The study was carried out at the Kenya Agricultural and Livestock Research Organization, Coffee Research Institute (KALRO-CRI) farm in Bungoma County, Kenya. The coffee management levels were categorized depending on field operations and application of inputs. The different shade levels were based on the distances from the trunk of shade tree and shading levels were estimated by measuring the Photosynthetic Photon Flux Density (PPFD) in µmol m-2 s-1 using a Line Quantum Sensor. The sensory characteristics fragrance/aroma, flavor, aftertaste, acidity, body, balance and overall were assessed by a panel of seven trained judges. The beverage quality, except for acidity and balance, were largely unaffected by management or shade levels, however trends showed that most of the variables, on average, had higher scores in shade than in full sun. Shade was positively correlated with all sensory variables while management was negatively correlated with all. This suggested that use of shade, under low management, could offset the limited application of external inputs to some extent. Keywords: Coffea arabica, shade, management levels and quality
The Effects of packaging materials on keeping quality of cassava root - leaf flakes
No full textProcessing and value addition is necessary for fresh agricultural commodities in order to reduce perishability and prolong shelf-life. Shelf life is enhanced with proper packaging because packaging materials influence storage period, preserve nutrients and sensory qualities. This paper objectively determined the effects of packaging materials on nutrients quality of cassava flakes. The methodology of the work involved the use of blends of cassava flakes packaged in Kraft, insulated polythene and plastic, and stored in an incubator at 550C and 75 % relative humidity for 5 days. Three blends of cassava flakes identified by panelists as the most preferred (20 % leaf, 100 % fresh root, 100 % fermented roots were developed and studied on accelerated shelf life trial. Storage period and packaging material were determined. The results showed moisture content to be significantly influenced by packaging material whereby it increased over the storage period, across the blends, with highest levels (10.75-%) registered in kraft material on day 3. After day 3 all nutrients showed a drastic decreasing trend with the most affected being protein that dropped from; 22.94 mg / 100g to 8 mg / 100g in the blend containing 20 % leaf in and 6.65 mg / 100g to 2. 8 in the blend of 100 % fresh root packaged in kraft materials. There was Paper insulated polythene (gunny) was shown to contain highest nutrients’ levels by day 5 with; protein at 27.68 mg /100g vitamins A (576.85 mg/100 kg), Zinc (1.17 mg /100 g), iron 3.69 mg /100g), fibre 6.12 mg /100g. Fat was highest at 9.71 mg/100g in the plastic material. The study therefore concluded that insulated polythene is the best packaging material for cassava flakes and the product’s shelf life is up to 3 months.
Formulation, of cassava root - leaf flakes, acceptability evaluation and determination of nutritional value
No full textCassava is an important food crop grown for its roots to supply daily needed calories to households in the cassava growing communities including coastal Kenya. The region contributes up to 30 % of the national cassava production though it remains food insecure with a high prevalence of malnutrition. Cassava roots are deficient in most nutrients except carbohydrates while the leaves are rich in a range of nutrients including protein but are moderately consumed as vegetables. The study sought to establish the most acceptable cassava root-leaf blend/s with improved nutrients’ content. This involved formulation of blends of cassava flakes through mixing roots and leaves in varying levels ranging from 0 % to 50 % that led to 18 different blends, with most accepted being 20%. Fermented and unfermented flakes were developed. A total of 18 formulations were developed before consumer acceptability and nutritional content were determined in the most preferred blends. The results showed cassava root-leaf flakes were best accepted when fermented root material is blended with 20% leaf component. Percent leaf content above 40% was unacceptable as such blends exuded poor smell. A calculation from the nutrients contained in blend 100 5 cassava roots against the blend that contained leaf material showed that the nutritional value showed that cassava root-leaf flakes have vitamins A and C improved by 353% and 53%, minerals- iron and zinc by 5.6% and 85% respectively and protein by 430% when compared with flakes processed from 100% cassava root. It is recommended that more studies be carried out to determine the bioavailability and nutritional effect of consumption of the flakes on children and pregnant women.
Farmer Perception and Adaptation Strategies on Climate Change in Lower Eastern Kenya: A Case of Finger Millet (Eleusine coracana (L.) Gaertn) Production
No full textEffects of pit, dark and cold pre-storage treatments and their duration on dormancy breaking and sprouting of seed potato tubers (Solanum tuberosum L.)
No full textPotato is the second most important food crop after maize in Kenya. In the traditional areas of
potato production with a bimodal rainfall pattern in the country, poor sprouting, due to seed tuber
dormancy, is a major drawback. There is little time between growing seasons to permit adequate
sprouting of the seed tubers. Therefore, effects of pit, dark and cold pre-storage treatments and
their duration on dormancy breaking and sprouting of seed potato tubers of variety Asante were
determined. Tubers were evaluated for sprouting, number of sprouts per tuber and sprout vigor
for 12 weeks. Pit and dark pre-storage treatments resulted in significantly higher sprouting,
number of sprouts per tuber and vigor scores than cold pre-storage treatment and the control
(diffused light storage). 100% sprouting of seed potato tubers was attained under pit storage by
the fourth week for all pre-storage treatment durations while dormancy ended after 6 weeks of
storage in the control. Sprouting was suppressed during cold pre-storage treatment. In pit and
dark pre-storage treatments, vigor scores increased with increasing duration of pre-storage
treatment while in the cold, vigor scores were reduced with longer pre-storage treatment
duration. Pit and dark pre-storage treatments for short durations of up to one week respectively
followed by two weeks of diffused light storage are recommended to break dormancy and
promote sprouting of good quality seed potato tubers of Asante variety
Influence of Crop Age on Nutritional Quality and Hydrogen Cyanide Levels of Roots from Popular Coastal Kenyan Cassava Varieties
No full textThe research activities were funded by National Commission for Science, Technology and Innovation (NACOSTI) 2015/2016 FY, laboratory reagents were funded by East African Agricultural Productivity Project (EAAPP) Abstract Cassava is an important crop in coastal Kenya commonly harvested at 12 months after planting but earlier during food shortages. There is limited information that addresses the effect of early harvesting on root quality especially for newly released varieties. Varieties Tajirika, Karembo and Kibanda Meno (roots) were harvested at different ages from Research Centres, studied for nutritional quality and hydrogen cyanide levels for safe utilization. Results showed significant (p < 0.05) interaction effect of varieties and crop age on studied nutrients. Karembo and Tajirika had peak dry matter of 43.42% and 41.42% respectively at 12 months while the peak for Kibanda Meno was 44.99% at 9 months. Mean starch content varied with variety; Karembo (91.3%), Kibanda Meno (93.4%), and Tajirika (85.5%). Karembo and Tajirika had peak carbohydrates at 12 months while the peak for Kibanda Meno was at 9 months. Vitamin C was highest at 6 months for Karembo (6.4 mg/100g) and Kibanda Meno (66 mg/100g). Tajirika had highest vitamin C (7.0 mg/100g) at 9 months. Iron was peak at 3 months for Karembo (3.63 mg/100g) and Tajirika (5.33 mg/100g) but at 9 months for Kibanda Meno (7.12 mg/100g). Peak Zinc was 2.1 mg/100g for Karembo at 6 months while for Kibanda Meno (1.94 mg/ 100g) and Tajirika (1.75mg /100g) at 12 months. Hydrogen cyanide increased from 8.6 to 9.3 mg/kg in Karembo between 9 and 12 months, it decreased from 7.8 to 5.2 mg/kg and from 5.1 to 4.5 mg/kg in Tajirika and Kibanda Meno, respectively. Harvesting of cassava roots should be staggered across crop ages to maximize on peaks of different root nutrients and processing is important. Keywords: Cassava varieties, roots, nutrients, hydrogen cyanide, months after planting DOI: 10.7176/FSQM/88-04 Publication date:July 31st 201
