Maria Carolina Dario Vitti

Intermittent warming in ‘Tahiti’ lime treated with an ethylene inhibitor

The storage of ‘Tahiti’ lime under low temperatures allows the marketing period to be extended, however, the loss of the green skin color and the occurrence of chilling injuries (CI) prevent such improvement to be achieved. The purpose of this work was to verify the efficiency of intermittent warming (IW) associated with the use of 1-methylcyclopropene (1-MCP) during the cold storage of ‘Tahiti’ lime. Fruit were treated for 12 h with 1-MCP at concentrations of 0 or 1.0 μl l−1 and then were stored at 5 °C. The fruit were submitted to IW (20 °C for 48 h every 7 days, 20 °C for 48 h every 14 days or 38 °C for 24 h every 14 days). Evaluations were carried out after 30, 60 and 90 days of storage (+3 days of simulated marketing at 20 °C). The occurrence of CI in the fruit was not observed after 30 days of storage, however, after 60 days of storage 40–58% of fruit kept continuously at 5 °C and 12.5–20% of fruit intermittent warmed showed CI. All fruit exhibited CI after 90 days. Warming fruit at 38 °C for 24 h every 14 days caused rot development, loss of green skin color, high respiratory rates, as well as accumulation of high levels of ethanol and acetaldehyde in fruit. Application of 1-MCP improved the maintenance of green color of skin.

Aspectos fisiológicos e microbiológicos de beterrabas minimamente processadas

The aim of this work was to evaluate physiological and microbiological aspects of fresh cut beet roots. Respiratory activity and ethylene evolution were evaluated during four hours after processing and during the storage period of ten days at 5 o C. Microbiological analysis was carried out right after processing and after ten days of storage. Intact roots showed the lower respiratory activity (5 mL CO 2 kg -1 h -1 ), whereas shredded and peeled beet roots presented a respiration rate of 30 mL CO 2 kg -1 h -1 four hours after processing. Fresh cut beet roots showed a peak during the second storage day (80 mL CO 2 kg -1 h -1 ), reducing to 30 mL CO2 kg -1 h -1 at the fourth day. No ethylene evolution was detected in intact and peeled beet roots whereas in the fresh cut material it was observed in the first hours after processing, reaching 0.90 µL kg -1 h -1 . Few variations were observed during the four-hour period after processing and during the refrigerated storage. Psychotrophic bacteria and total coliforms counts were within acceptable limits, and no Salmonella or fecal coliforms were detected.

Quality of minimally processed beet roots stored in different temperatures

ABSTRACT The present work was carried out with the objective to determine the effect of different storage temperature on thequality of beet root minimally processed. Respiratory activity and mass loss were higher in the storage at 15 o C. Nosignificant differences in color, total soluble solids, betacyanin and betaxanthin were observed among treatments.Based on the results obtained, the storage at 0 o C was recommended to storage beet root minimally processed andthat 10 and 15 o C drastically reduced the quality of minimally processed beet roots during storage.Key words: Beta vulgaris L., fresh-cut, betalains, respiratory rate * Auth or for c respondence INTRODUCTION Beet is a root vegetable of the Chenopodiaceaefamily whose edible part is its tuberous root. Itspurple-red color is due to the presence of betalainpigments. These pigments are similar toanthocyanins and flavonoids, which were wronglytermed in the old literature as anthocyaninscontaining nitrogen. Betalains are water-solublepigments and are found only in ten families of theCentrospermae group and are divided into twoclasses: red betacyanin and yellow betaxanthin,which provide beet roots with their typical color(Fenena, 1995). Besides, these pigments oftenexhibit antioxidant activity and potential healthbenefits of vegetables (Kanner et al., 2001).Minimal processing (fresh-cut) comprisesselection, washing, peeling and cutting proceduresthat are aimed at producing a product that is freshand convenient to prepare and consume (Burns,1995). Minimally processed fruits and vegetablesare more perishable than their whole counterparts,due to undergoing severe physical stressesespecially during peeling and cutting procedures.Cutting, associated with high storage temperatures,leads to an increase in the respiratory rate, with anincrease in the activity of enzymes involved inspecific reactions (Chitarra, 1998).Temperature control is the most common andimportant technology to minimize the effects ofcutting in fruits and vegetables (Brecht, 1995).Whole and sliced carrots kept at 0 and 10

Comportamento da beterraba minimamente processada em diferentes espessuras de corte

ABSTRACT Quality of minimally processed beet roots in different cutthickness The quality of minimally processed beet roots with different cutthickness was evaluted. The roots were processed with 2; 5 and 8mm thickness: After the preparation, the cut beets were conditionedin expanded polystyrene trays and stored at 5°C during 10 days. Theexperimental design was completely randomized in factorialarrangement. Every 2 days, the minimally processed roots wereevaluated for total soluble solids contents, weight loss, coloration,appearance, betacyanin and betaxanthin content and respiratory rate.The total soluble solid content was higher for beets cut with 8 mmthickness. There was no statistic difference among the treatments inrelation to coloration, betacyanin and betaxanthin contents andrespiratory rate. Good quality of minimally processed beet roots canbe maintained until the 6 th day of storage, independent of the cuttingthickness. Keywords: Beta vulgaris L., fresh-cut, respiration, pigments.

Efeito do momento de sanitização sobre atributos fisico-químicos e microbiológicos de beterrabas minimamente processadas

Early Wonder beet roots were minimally processed and submitted to sanitization treatments: control (no sanitization); sanitization after cutting (standard); sanitization before peeling and after cutting; sanitization only after peeling; sanitization before and after peeling; sanitization before and after peeling and after cut. After the treatments, the product was placed on trays wrapped in PVC film and stored at 5±1°C and 85±5% RH for 10 days. Physicochemical and microbiological analyses were conducted during refrigerated storage. Fecal coliforms and Salmonella were not detected in beet roots that underwent sanitization. Total coliforms and psychotropic bacteria counts, as well as betacyanin and betaxanthin amounts were higher in non-sanitized beet roots. There was a decrease in pigment amounts during storage. Post-peeling sanitization is the most suitable for quality maintenance, as it reduces pigment loss, ensures good food safety standards and avoids chlorine waste.

Armazenamento refrigerado de beterraba minimamente processada em diferentes tipos de corte

Fresh cut beetroot showed low shelf life, even under refrigeration, and the main quality depreciative factor is the superficial discoloration (white blush) that depreciates the quality of the product. The objective of this research was to verify the effect of three cut types on quality of the minimally processed beetroot during cold storage. The cut types used were slice, cube and shred. After processing, the beetroots were stored at 5°C during ten days and the evaluations were carried out each two days. Sliced beetroots showed higher respiratory rate and higher losses of betalains and soluble solids during cold storage. Visual quality of minimally processed beetroot was preserved up to four days of storage in both cut type. The main factor that has caused loss of quality of this vegetable was the incidence of white blush. It can be concluded that the beet minimally processed in slices or cube presents conservation of, at the most 4 days to 5°C, while minimally processed in shred it presents 6 days of conservation.

Activity of enzymes associated with the enzymatic browning of minimally processed potatoes

The purpose of the present study was to evaluate th e effect of different potato cultivars and storage temperatures on the specific activity of phenylalanine ammonia-lyas e (PAL), polyphenol oxidase (PPO) and peroxidase (P OD) in minimally processed potatoes. Potato cultivars Agat a, Asterix and Monalisa were selected, washed, peel ed, diced, sanitized, centrifuged, vacuum- packed and stored a5 and 15°C for 9 and 5 days, respectively. There was an increase in the enzymatic activity in all the cultivars stored at 15°C. The cultivars ‘Agata’ and ‘Ast erix’ stored at 5oC did not differ significantly between them for tPAL, PPO and POD activities. The PAL, PPO and PO D activities were also influenced by the storage temp erature. The cultivars Agata and Asterix were more suitable in minimal processing than ‘Monalisa’, which was more susceptible to oxidative browning.

Respiratory activity and pigment metabolism in fresh-cut beet roots treated with citric acid

Beet roots cv. Early Wonder were graded for firmness, color and size, and were peeled inside a cold room (10°C). Roots were then shredded (2 mm thick), sanitized for 6 minutes (NaClO/200 mg L -1 ), rinsed and centrifuged. Fresh-cut beet roots were then treated for 5 minutes with citric acid in the following concentrations: 0 (control), 500; 1,000; 1,500 and 2,000 mg L -1 . The material was centrifuged again, placed in trays, wrapped with PVC plastic film, and stored at 5°C and 85-90% HR for 10 days. Every two days, treatments were analyzed for respiratory activity and betacyanin and betaxanthin contents. The application of citric acid caused the reduction of respiratory rate in the fresh-cut tissue. In the second day of storage, control showed the highest respiratory activity among treatments, reaching around 77 mL CO 2 kg -1 h -1 . Citric acid solution dips in a concentration higher than 500 mg L -1 contributed to a decrease in respiratory activity and no peak in CO 2 evolution was observed. There were significant differences among all treatments during the storage period for the contents of betacyanin, which were around 40; 45; 48; 51 and 55 mg 100 g -1 for the fresh-cut material treated with 0; 500; 1,000; 1,500 and 2,000 mg L -1 of citric acid, respectively. Also, levels of betaxanthin were around 25; 29; 33; 35 and 39 mg 100 g -1 for the material treated with 0; 500; 1,000; 1,500 and 2,000 mg L -1 of citric acid, respectively. The application of citric acid after minimal processing apparently have the ability to reduce respiratory rate and the degradation of pigments, which contributes to extend the shelf life of the fresh-cut product.