Physical, Chemical and Microbial Changes in Shredded Sweet Potatoes+

Abstract

With the increasing demand for freshly cut vegetables, a substantial potential exists in developing minimally processed sweet potato products. This study was undertaken to determine the effects of semipermeable polymeric materials and modified atmosphere packaging (MAP) on quality changes and microbial growth in shredded sweet potatoes under refrigerated storage. Shredded sweet potatoes from two major commercial cultivars (Beauregard and Hernandez) were packed in low and medium O 2 permeability bags and flushed with gas composed of 5% O 2 , 4% CO 2 and 91% N 2 . Quality changes and microbial growth were monitored in comparison to the samples packed in air using high‐O 2 permeable films. The quality of shredded sweet potatoes could be maintained for 7 days at 4C in air, but extended up to 14 days in MAP. Considering the parameters measured in this investigation, the best results were obtained by MAP using moderately O 2 ‐permeable film (7000 cm 3 /atm/m 2 /24 h). Shredded sweet potatoes stored in MAP showed less changes in tissue firmness, dry matter, ascorbic acid and starch than shredded sweet potatoes stored in air. The MAP‐stored shredded sweet potatoes consistently exhibited fewer total aerobic bacteria and enteric bacteria compared to the shredded sweet potatoes stored in air. Yeasts, molds, lactic acid bacteria, color, beta‐carotene and sugars of all stored shredded sweet potatoes did not significantly change, regardless of treatments. Higher ethanol levels were generated in the MAP‐stored shredded sweet potatoes after 10 days, but off‐odors were not detected in any of the MAP‐stored shredded sweet potatoes.

Effects of sodium metabisulphite and citric acid on the shelf life of fresh cut sweet potatoes

“…2). McConnell et al (2005) working with mashed sweet potatoes multilayer polyolefin bags packed, with an average permeability of O 2 and MAP, found decreases of 11% to 15% in the ascorbic acid content after 14 days at 4°C. In six cultivars of stripped potatoes packed in MAP, on the sixth day of storage at 4°C, Tudela et al (2002) reported a loss between 14% and 34% and it was different when product was stored in contact with air.…”

“…According to McConnell et al (2005), low luminosity or brightness values (L*) would indicate a greater degree of browning in cut vegetables. In experiences done in mashed sweet packed potatoes and stored at refrigeration temperatures, they did not detect changes in the L* value.…”

“…In sliced apples, the combined addition of sulphites and calcium ions improved the firmness and color (Ponting et al, 1971). McConnell et al (2005) reported smaller microbiological load in shredded sweet potatoes stored in modified atmosphere packaging (MAP) when compared to shred sweet potatoes stored in air and no changes in color, β-carotene and sugars were found regardless of package atmospheres. Other authors reported the reduction of population of mesophiles, psychrotophs and yeast-moulds during 14 days in sweet potatoes slices dipped with 200 mg L -1 chlorine stored at 1°C (Erturk and Picha, 2006).…”

Crops that feed the world 5. Sweetpotato. Sweetpotatoes for income and food security

“…Storage of roots at <12°C results in chilling injury (Picha 1987). Roots can also be stored under controlled atmosphere conditions (Mcconnell et al 2005). Uncured roots decayed rapidly when stored at low O 2 tensions but, after curing, O 2 tensions of 2 and 4% did not appear to be harmful (Delate and Brecht 1989).…”

Application of Modified Atmosphere Packaging on Quality of Selected Vegetables: A Review

“…B-carotene content of fresh-cut sweet potatoes at the end of storage had an average of 6.01 mg per 100 g of FW (Erturk and Picha 2007 ). McConnell et al ( 2005 ) packed shredded sweet potatoes from two major commercial cultivars ('Beauregard' and 'Hernandez') in low (PD-900) and medium (PD-961) O 2 permeability bags at 4 °C and fl ushed them with gas composed of 5 % O 2 and 4 % CO 2 . Samples from 'Beauregard' and 'Hernandez' cultivars stored under MAP did not undergo any change in ascorbic acid contents (15.4 and 14.7 mg/100 g, respectively).…”