|Abstract or Summary
- Peas (Pisum sativum) are an important constituent in the diet
of many people. Peas may be cooked and eaten as green peas shortly
after harvest, stored for short periods in the pods, or, after suitable
treatment, stored for long periods before consumption. Many factors
influence the yield and quality of frozen peas but maturity
requires careful consideration because of the relation of maturity
to color, flavor, and texture.
The objectives of this thesis were to determine the effect of the
maturity stage on the quality of the frozen peas during processing and
storage and to correlate the interactions between the sensory evaluation
panel with the physical and chemical quality factors measured.
Venus pea variety grown under commercial conditions at the
Sublimity area east of Salem, Oregon, were used in this study. The
trials were randomized, for three stages of maturity with three replications
per each stage of maturity. Each of the three maturity stages
was harvested; vined; blanched by steaming at 98.8°C (210°F) for
30 sec for the immature peas, 60 sec for the mature peas, and 90 sec
for the overmature peas; frozen at -37.2°C (-35°F) for 24 hr in an air
blast freezer and stored at -23.3°C (-10°F) for 4 and 8 month. During
processing and. storage the following factors were determined:
tenderometer value, total solids, alcohol insoluble solids, peroxidase
activity, ascorbic acid., total sugars and sensory evaluation. In the
sensory evaluation analysis starchiness, sweetness and tenderness
intensity, as well as texture, flavor and overall desirability were
measured. Analysis of variance and least significant difference were
used to compare the effect of pea maturity during processing and
storage on the different quality factors measured. Correlation coefficients
were used to determine the relationship between these factors.
Immature peas had lower tenderometer value than overmature
peas. Tenderometer value of peas decreased, during processing. The
highest total solids content was observed, in the overmature peas and
the lowest total solids content in the immature peas. This behavior
was also observed in the alcohol insoluble solids content.
Raw peas in the three maturity stages had the same initial
peroxidase activity and the significant effect of the maturity level
found in the residual peroxidase was affected by the different blanching
time applied at each maturity stage. The ascorbic acid content
was significantly affected, by the maturity level and was reduced
during the blanching treatment. Total soluble sugar content was
higher in immature peas and lower in overmature peas.
All the sensory evaluation parameters measured were affected
by the maturity. In general, the taste panel found higher flavor desirability
on the mature peas but when texture and overall desirability
were measured immature and mature peas were equally preferred.
Significant correlations were found between physical, chemical,
and sensory parameters analyzed, some of them are tenderometer
value and alcohol insoluble solids; total solids and alcohol insoluble
solids; alcohol insoluble solids and overall desirability.