|Abstract or Summary
- The effect of entrapped air content on heat penetration
characteristics in institutional size retortable pouches
packed with pears and green beans was investigated. In
addition, products processed in pouches and in number 10
cans were compared using several indices of quality (color,
texture, total phenolics, ascorbic acid) and sensory panel
Heat penetration studies were conducted in an FMC Laboratory
Retort. Pouches were placed in horizontal orientation,
using both constrained and restrained racking methods. For
green beans, a retort temperature of 121°C and 0.68 Atm (25
psig) overriding pressure, of steam and air, were used for
processing. For pears a retort temperature of 98°C and
0.68 Atm (10 psig) overriding pressure, of air, were used.
For both products, thermal processing times were found to
increase approximately 15 % for each 100 milliliter increase
in entrapped air content, under constrained conditions.
When restrained the increases were much larger. A
Stock Rotomat laboratory retort which allowed the pouches
to be rotated was also used. Two studies were done: first,
pouches were rotated at 15 rpm, second, they were still retorted
in vertical orientation. When rotated, the processing
times were about one-third those obtained in the FMC retort.
When the pouches were processed in vertical orientation
little change in process time was noticeable even with large
amounts of air, entrapped within the pouch.
Color of samples was measured by reflectance to obtain
Hunter values. An Allo-Kramer shear press was used to measure
the texture or firmness of both pears and green beans.
Total phenolics were measured using the Folin-Ciocalteu
method. The results showed that pears processed in the
presence of air will darken.
In comparing products from retortable pouches with those
from number 10 cans which had been processed from the same
processing lot of raw product, it was found that generally
the canned products were better than those processed in the
pouch, however differences were slight.
Results of this study suggested that in order to obtain
a better product from institutional size retortable pouches
it is necessary to minimize the amount of air entrapped
within the pouch.