American Journal of Food Science and Technology

The quality of extra virgin olive oil (EVOO) is intimately affected by packaging material and storage temperature. In this study, the influence of packaging materials and elevated temperature on EVOO quality was investigated during six months. At ambient temperatures, oil maintained EVOO when stored in glass, polyethylene terephthalate (PET), high density polyethylene (HDPE), cans and Pottery in terms of chemical tests (acidity, peroxide value, K₂₃₂, and K₂₇₀). Loss of phenols was the highest in pottery-stored oil and the lowest was found in glass-stored oil. Only PET-stored oil maintained the EVOO grade in terms of sensory evaluation when stored at room temperature. At elevated temperature, oil stored in all packaging materials lost extra virgin quality in terms of chemical tests. The loss of phenols was the largest in HDPE and smallest in cans-stored oil. Sensory evaluation, maintained glass-stored oil and PET-stored oil as EVOO. This study has reaffirmed that at both storage temperatures, the best container in maintaining the EVOO quality was glass and the worst was pottery. Grading of stored olive oil under investigation using sensory evaluation solely was not sufficient. Also it was clear that the absorption coefficient K₂₇₀ was the most sensitive determinant chemical test that determines the quality of stored olive oil and could be used as a rapid indicator test.

American Journal of Food Science and Technology. 2014, 2(5), 162-174. DOI: 10.12691/ajfst-2-5-5
Pub. Date: November 06, 2014

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Preserving Strawberry (Fragaria Ananasa) Using Alginate and Soy Based Edible Coatings

by Waqas Ahmed and Masood Sadiq Butt

Original Research

Instant research project was an attempt to address the postharvest losses in strawberry using the concept of biodegradable edible coatings. Purposely, alginate and soy based coatings were developed at various levels (2, 2.5 and 3%) and assessed for the role in controlling the moisture loss and total solids in the coated fruit. From results, it was deduced that moisture loss was lowered to 4.86% in T₃ (Soy 3%) as compared to 13.45% in T₀ (Control) for strawberry kept at controlled climate chamber. Likewise, 2.5 and 3% combinations of soy and alginate based coatings were found efficient in maintaining overall solids content of the coated strawberry.Based on the findings, edible coatings are suggested as an innovative, cost effective and environmental friendly preservation technique that holds potential to be used on fresh perishable commodities.

American Journal of Food Science and Technology. 2014, 2(5), 158-161. DOI: 10.12691/ajfst-2-5-4
Pub. Date: November 05, 2014

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Soaking and Drying Effect on the Functional Properties of Ogi Produce from Some Selected Maize Varieties

by Bolaji O.T., Oyewo A.O and Adepoju P.A

Review Article

This study evaluated the effect of soaking period (12, 24 and 36 hours) and drying temperature (40,50 and 60°C) on the functional properties of Ogi powder produced from four different maize varieties; A5W, A4Y, D1Y and S7Y. The moisture content and drying rate decreased significantly (p< 0.05) with increase in time and drying temperature. There were no significant difference (p>0.05) in Bulk Density, Sedimentation and Swelling Power. The result revealed that sedimentation volumes were not influenced by processing methods while starch damage of the Ogi powders varies from 92.03 to 95.02%. This increased with increase in drying temperature. Ogi powders had least gelation of 8% for all the maize varieties. There were significant differences (p<0.05) in Viscosity, Solubility, Water Absorption Capacities (WAC) and Oil Absorption Capacities (OAC). Ogi powder produced from A4Y variety and soaked for 12 hours exhibited higher WAC values at 50°C. This variety also displayed higher values of water absorption capacity at all temperatures. Solubility, viscosity and swelling power increased with increase in temperature. The viscosity of the Ogi powders pastes ranged from 1200-1794 cps, and 804- 1540 at 80 and 30°C, respectively. Ogi powders produced from D1Y and S7Y exhibited higher degree of retrogradation. Differences observed in the functional properties among varieties highlight the possible application of end-product suitability in Ogi powder processing.

American Journal of Food Science and Technology. 2014, 2(5), 150-157. DOI: 10.12691/ajfst-2-5-3
Pub. Date: November 04, 2014

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Microbiological and Sensory Profile of Soymilk Based Juice Treated with Liquid Extract of A. Danielli

by Dauda A.O and Adegoke G.O.

Original Research

The microbiological and sensory profile soymilk-based juice treated with aqueous extract of Aframomum danielli (1%-3%-w/v) and stored at 27±2C for twenty four weeks were examined. Synthetic additives/preservatives, which have been in use over the years, are more expensive and mostly imported with hard earned scarce foreign exchange. Adequate research work into the production and utilization of indigenous food additives on a large scale has not been undertaken in developing countries. This work was therefore planned to ascertain the usefulness of extracts of A. danielli, a local spice, in stabilizing the microbiological quality of soymilk-based juice. Standard methods were used for the production of juice samples from pineapple, orange, carrot and milk from soybeans. They were blended together in equal proportion and thereafter treated with A. danielli extract (1.0% to 3.0%) and stored at 27+2C for twenty four weeks. Infrared spectrophotometer was used to identify functional groups in Aframomum danielli and hence the active components responsible for the stability of the juice. Standard AOAC method was used for microbiological analysis of treated and untreated samples. Consumer evaluation of juice samples was done using analysis of variance (ANOVA). Some of the active components of the spice identified are 4-amino-acetophenone, N,N-dimethyl-2-chloroacetoacetamide, 3-beta-acetoxy-5-etienic acid, 6,10-dimethylundeca-5,9,-diene2-one, Phenyl-3-buten and 4-Phenyl butanone. There were significant differences in the microbial counts of the treated and untreated samples. Treated samples experienced little or no growth over the period of storage. The results validate previous reports that A. danielli extract has great preservative potentials. There were significant differences (P < 0.5) for colour and overall acceptability of the samples. When A. danielli extract was added to soymilk-based fruit juice, the microbiological and sensory qualities were found to be better preserved than that of the untreated samples.

American Journal of Food Science and Technology. 2014, 2(5), 145-149. DOI: 10.12691/ajfst-2-5-2
Pub. Date: October 15, 2014

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Heavy Metal Contamination in Green Leafy Vegetables Collected from Selected Market Sites of Piliyandala Area, Colombo District, Sri Lanka

by Thilini Kananke, Jagath Wansapala and Anil Gunaratne

Original Research

The content of nickel (Ni), cadmium (Cd), chromium (Cr), lead (Pb) and copper (Cu) in five different types of green leafy vegetables viz., “Kangkung" (Ipomoea aquatica), "Mukunuwenna" (Alternanthera sessilis), "Thampala" (Amaranthus viridis), "Nivithi" (Basella alba) and “Kohila” (Lasia spinosa) collected from four randomly selected urban and sub urban market sites in and around Piliyandala area of Colombo District, Sri Lanka, were measured using atomic absorption spectrometry. The results showed significant differences in elemental concentrations among the green leafy vegetables analyzed. The average concentrations of heavy metals detected in green leafy vegetables ranged from 0.71-15.89, 0.07-0.97, 0.18-5.05, 0.18-1.59, 7.05-18.44 mg/kg for Ni, Cd, Cr, Pb and Cu respectively, on dry matter basis. In addition, the mean concentrations of metals in the green leafy vegetables were found in the order of their abundance as Cu>Ni>Cr>Pb>Cd. However, there were no significant differences (p < 0.05) between the heavy metal contents in combined green leafy vegetables collected from the four market sites. It was also found that the Ni, Cd, Cr and Pb levels exceeded the maximum permissible limits set by FAO/WHO for human consumption.

American Journal of Food Science and Technology. 2014, 2(5), 139-144. DOI: 10.12691/ajfst-2-5-1
Pub. Date: September 22, 2014

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