Shelf life of fresh-cut spinach as affected by chemical treatment and type of packaging film

Abstract

-Fresh-cut vegetables are an important and rapidly developing class of convenience foods. Their storage life may be greatly reduced due to their high rates of respiration and transpiration and the possibility of enzymatic and microbiological deterioration. Consequently, the objective of this work was to determine the shelf life and the failure attribute that conditioned the shelf life of fresh-cut spinach treated with chemical solutions and packaged in bags with different permeabilities. The shelf life of fresh-cut vegetables was defined as the time of refrigerated storage at which any one of the sensory attributes scored below 7 or when the microbiological counts exceeded 5.10 7 CFU/g. Fresh-cut spinach was treated with citric acid and ascorbic acid solutions and packaged in mono-oriented polypropylene (OPP) bags or low-density polyethylene (LDPE) bags. Sensory attributes and total microbial counts were evaluated throughout refrigerated storage. Response surface methodology (RSM) was used to study the simultaneous effect of chemical treatment and refrigerated storage time on sensory and microbiological quality of fresh-cut spinach. A quadratic polynomial regression model was assumed for predicting off-odor, general appearance, wilting, browning, color, and mesophilic aerobic population. Type of packaging film only influenced development of off-odor (p≤0.001) and had no effect on visual sensory attributes or microbiological counts (p>0.05). Development of off-odor was the attribute that limited shelf life of fresh-cut spinach packaged in OPP bags. On the other hand, shelf life of samples packaged in LDPE bags was dependent on a decrease in general appearance or an increase in microbiological counts, depending on the chemical treatment used.

Influence of Storage Conditions on Sensory Shelf Life of Yerba Mate

“…Unlike other foods in which changes of general appearance are deterioration indicators (Piga et al 2000;Piagentini and Güemes 2002;Jiang et al 2005;Lee and Resurrección 2006), changes in YM appearance (color and agglomeration) were not associated to food rejection for storage time and moisture content used in the present study.…”

“…In the case of a trained panel, the number of judges is smaller, a hedonic scale can be used and a considerable number of specific attributes in the description of the sensory profile can be used (Al‐Kadamany et al. 2002, 2003; Piagentini and Güemes 2002; Santa Cruz et al. 2003).…”

“…In the first case, a large number of consumers is needed and, in general, is limited to acceptance test (Vankerschaver et al 1996). In the case of a trained panel, the number of judges is smaller, a hedonic scale can be used and a considerable number of specific attributes in the description of the sensory profile can be used (Al-Kadamany et al 2002Piagentini and Güemes 2002;Santa Cruz et al 2003). The use of the trained panel allows the finding of the main failure attributes for a specific food (Hough et al 1999).…”

Mechanical Properties of Spinach

“…Cold storage was used to store the spinach for predetermined temperature at 4 ºC and 90% relative humidity for storage period of fourteen days (Piagentini, 2002).…”

Conservação de abacaxi minimamente processado utilizando como coadjuvantes cloreto de cálcio, película comestível e radiação gama

“…A refrigeração (MARRERO; KADER, 2006;O'CONNOR-SHAW et al, 1994), atmosfera modificada (CARLIN et al, 1990;GIL;CONESA;ARTÉS, 2002;IZUMI et al, 1996;SIRO et al, 2006;KADER, 1988), tratamentos químicos (BUDU;JOYCE, 2003;ESWARANANDAM;HETTIARACHCHY;MEULLENET, 2006;PIAGENTINI;GÜEMES, 2002), películas comestíveis (CUTTER, 2006;FONTES;SARMENTO;SPOTO, 2007;GONTARD et al, 1994;NUSSINOVITCH et al, 1997;PARK, 1999), e a radiação gama (GUNES et al, 2000;LAFORTUNE et al, 2005;OUATTARA et al, 2002;WANG et al, 2006) A temperatura de refrigeração abaixo de 7ºC, utilizada no armazenamento de frutas e hortaliças minimamente processadas, embora prolongue a vida útil desses produtos, diminuindo a velocidade de crescimento dos microrganismos, são seletivas para microrganismos psicrotróficos. A presença de bactérias mesófilas e psicrotróficas em alface, repolho e chicória, foi relatada por alguns autores (NGUYEN-THE et al, 1996;ZHANG;FARBER, 1996).…”