Effect of Water Activity and Packaging Material on the Quality of Dehydrated Taro (Colocasia esculenta (L.) Schott) Slices during Accelerated Storage.

The quality of dehydrated taro slices in accelerated storage (45°C and 75% RH) was determined as a function of initial water activity (aw) and package type. Color, rehydration capacity, thiamin content, and α-tocopherol content were monitored during 34 weeks of storage in polyethylene and foil laminate packaging at initial storage aw of 0.35 to 0.71. Initial aw at or below 0.54 resulted in less browning and higher rehydration capacity, but not in significantly higher α-tocopherol retention. Foil laminate pouches resulted in a higher rehydration capacity and increased thiamin retention compared to polyethylene bags. Type of packaging had no effect on the color of the samples. Product stability was highest when stored in foil laminate pouches at 0.4aw. Sensory panels were held to determine the acceptability of rehydrated taro slices using samples representative of the taro used in the analytical tests. A hedonic test on rehydrated taro's acceptability was conducted in Fiji, with panelists rating the product an average of 7.2 ± 1.5 on a discrete 9-point scale. Using a modified Weibull analysis (with 50% probability of product failure), it was determined that the shelf life of dehydrated taro stored at 45°C was 38.3 weeks.

Conditions associated with Clostridium sporogenes growth as a surrogate for Clostridium botulinum in nonthermally processed canned butter.

The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt levels and, therefore, home preparation of canned butter is not advisable. It is also possible that commercially canned butter, if heat abused, could potentially allow for C. botulinum growth and, therefore, consumption is not recommended.

Acceptance of brown-shelled eggs in a white-shelled egg market.

Brown eggs have gradually entered the traditional white-egg markets as a distinctive mode for packaging specialty eggs. A test was conducted at the Brigham Young University Sensory Laboratory (Provo, UT) to understand how consumers view attributes of the brown egg relative to the white egg. The objectives were to see how the consumer viewed properties of eggs by color and to examine the preference for brown color intensity. The 52 panelists were all women who routinely purchased and consumed eggs. Some women (53.8%) consumed eggs twice weekly, and 40.4% purchased them at least every 2 wk. Purchases included specialty eggs (14.6%) consisting of cage-free (50.0%), organic (28.6%), and n-3 enhanced (21.4%) eggs. The panelists preferred white eggs (90.4%). Though brown-shelled eggs did not exceed white eggs in preference, they were perceived positively (white-shelled %:brown-shelled %) as being more nutritious (65:29), having more flavor (27:14) and n-3 content (62:39), having a farm-flock origin (46:44), and being from organically fed hens (56:31) To test the preference for shade of brown eggs, a set of 6 eggs with varying intensities of brown color was evaluated for accepted appearance using a 9-point hedonic scale. The egg color intensities were measured using a Hunter Colorflex spectrophotometer (Hunter Associates Laboratory, Reston, VA) and the CIE system. The lightness (L*) values ranged from 83.2 for the white egg to 63.6 to 46.5 for the brown eggs. A significant (P < 0.05) preference was found for the 2 lighter shades of brown-shelled eggs (L* 63.6 and 57.5). Using the 9-point scale, panelists then compared brown eggs side by side with white eggs. Again, the 2 most light-tinted brown eggs were found most comparable with the white egg in acceptability and better (P < 0.05) than the darker brown eggs. In conclusion, white eggs were preferred over brown eggs; however, brown eggs gained in acceptance but did not exceed white as likely to be more nutritious or flavorful, fresher, organic, and of cage-free origin. Varying color shades in cartoned eggs was equally as acceptable as uniform colored eggs. Panelists preferred the appearance of the light-tinted brown eggs to that of darker brown eggs.

Sensory and nutritional quality of split peas (Pisum sativum) stored up to 34 y in residential storage.

The sensory and nutritional quality of split peas stored up to 34 y was determined. Nine samples of split peas representing 5 retail brands packaged in Nr 10 cans and stored at room temperature were obtained from donors. Duplicate cans of a fresh sample of split peas were purchased as controls. Can head space oxygen ranged from 0.255% to 20.1%. Water activity of the raw split peas ranged from 0.41 to 0.56. The green color of the raw split peas decreased over time as shown by increasing CIE a* values. Flavor, appearance, texture, and overall liking hedonic scores (9-point scale) of split-pea soup made from each sample ranged from 3.7 to 6.7 and decreased over time. Hedonic scores for appearance were correlated with the decrease in raw product green color (r(2)= 0.65). Hedonic scores for soup texture declined over time, which corresponded with increasing hardness of the cooked peas as measured by a TA.XT2 texture analyzer. All samples were judged to be acceptable in an emergency situation by over 75% of sensory panelists. Available thiamin was significantly lower in older samples while riboflavin remained unchanged. The results indicate that split pea quality declines over time, but the product maintains sufficient sensory acceptance to be considered for potential use in emergency storage and other applications where minimal stock rotation is a common practice.