EFFECT OF SOLAR DRYING ON THE COMPOSITION OF ESSENTIAL OIL OF SACHA CULANTRO (ERYNGIUM FOETIDUM L.) GROWN IN THE PERUVIAN AMAZON

Two solar drying methods (direct cabinet solar dryer and indirect cabinet solar dryer) were tested under tropical conditions for drying aerial parts of sacha culantro ( Eryngium foetidum L.) in Pucallpa City (Peruvian Amazon). The drying behavior was monitored during all experimental runs. Dried samples and fresh leaves were hydrodistilled and isolated oils were analyzed using gas chromatography with flame ionization detector and gas chromatography-mass spectrometry. ( E )-2-dodecenal was determined as the main constituent of the sacha culantro essential oil, averaging 61.8–62.2%, followed by n -dodecanal (10.9–15.5%), ( E )-2-tetradecenal (6.7–7.6%) and 1-tetradecene (3.6–5.7%). When comparing both solar drying methods, the indirect method was found as more suitable for drying E. foetidum since the dried product resembled the fresh herb more closely in its chemicalcomposition and had better appearance. However, a better drying efficiency of 10.3% was achieved when drying in the direct solar dryer compared with 5.8% for the indirect solar dryer.

PRACTICAL APPLICATIONS

Harvested leaves of sacha culantro are widely used as a condiment in a range of Peruvian, Latin American and Caribbean foods, including vegetable and meat dishes, canned food and sauces. There is lack of any postharvest processing of this herb although it may extend possibilities for use of the herb and facilitate the product export from local production areas and might be a good economic source for poor local farmers. This study shows solar drying as a reasonable preservation technique of sacha culantro leaves which may have a practical application in case of postharvest processing of the herb in the target region of Pucallpa City in Peruvian Amazon.     

STUDIES ON POSTHARVEST PHYSIOLOGY AND THE STORAGE TECHNOLOGY OF MANGO (MANGIFERA INDICA L.)

Mango (Mangifera indica L. cv. Hongxiangya and Wacheng) was chosen to study the effect of postharvest biological characters in different storage conditions. The determining items included respiratory rate, total sugar, vitamin C (Vc) content, firmness, polyphenol oxidase (PPO) and peroxidase (POD). The results showed that both 8 and 11C were the better storage temperatures, and the storage life would last 50 days in this situation. The respiration rate increased quickly between the 16th to the 22nd days; the peak values were the 28th and 25th days at 8C for Hongxiangya and Wacheng, respectively. The flesh firmness decreased dramatically at 6 days after harvest. Total sugar content, Vc content, PPO and POD increased at first and then decreased. The color changed from green to yellow with the increase of carotenoids content. After treatment with thiabendozole and iprodione, the number of rot fruits was markedly lower than the other treatments. The best temperature is 11 and 14C for Hongxiangya and Wacheng, respectively. The rot rate is 6.77 and 8.33% with 1,000‐ppm iprodine treatment after 50‐days storage.     

EFFECT OF POSTHARVEST HOT AIR AND FUNGICIDE TREATMENTS ON THE QUALITY OF 'MARADOL' PAPAYA (CARICA PAPAYA L.)

Papaya (Carica papaya L.) fruit is very perishable with a maximum postharvest life of 4 weeks. The effect of forced moist (100% RH) or dry (50%) hot air with or without Thiabendazole (TBZ at 1.2 g active ingredient/L) on the chilling injury (CI), fungi development and quality of ‘Maradol’papaya fruit stored at 5C or 20C for up to 42 days was investigated. Moist hot air at 48.5C or 50C for 4 h caused fruit injury. Dry air at 48.5C for 4 h, alone or in combination with TBZ, decreased CI intensity and fungi development, and the best effect was achieved by combining dry heat treatment and TBZ, without causing negative effects on fruit quality and without causing heat injury. Hot air treatment, especially in combination with TBZ, decreased growth of inoculated Colletotrichum gloeosporioides. Trehalose was not detected in papaya, probably due to the presence of trehalase. Hot water treatment, with or without TBZ, did not cause any negative effect on the content of β-carotene and lycopene.     

POSTHARVEST CHANGES OF PECTIC SUBSTANCES IN CHILLED PEACHES

ABSTRACT Red Globe peaches were harvested at the threshold-mature stage and either stored at OC after preripening at 20C for 48 h or stored directly at 2C. Total pectin increased from 7.49 mg/g fresh weight in the threshold-mature sample to 10.21 mg/g in pre-ripened fruit stored at OC and 12.83 mg/g in fruits stored directly at 2C. Depending on extraction and storage protocol, between 26% and 73% of total pectin was solubilized. Chelator-soluble fractions had a low degree of esterification (DE ca. 20%), whereas other fractions were highly methylated (DE ca. 56% to 74%). Average DE did not vary between samples. DEAE-cellulose chromatography revealed an uneven distribution of methoxyl groups. Two prominent peaks were observed in chromatograms of chelator-soluble extracts from threshold-mature fruit and fruit stored directly at 2C. One peak was observed in chelator-soluble pectin from preripened fruit stored at OC.     

RETARDATION OF OXIDATIVE COLOR CHANGES IN RAW GROUND BEEF

SUMMARY— Ascorbic acid plus either BHA or PG effectively retarded both lipid and pigment oxidation in raw ground beef for up to 8 days of refrigerator storage in oxygen-permeable film. Both trained and consumer-type panels judged the additive-treated meat to be significantly better than controls. Percent metmyoglobin was found to be a useful objective measurement of color in raw beef, but total pigment concentration did not provide an adequate evaluation of color. Treatment with these additives did not appear to mask bacterial spoilage.     

RADIO FREQUENCY PULSE APPLICATION FOR HEATING UNIFORMITY IN POSTHARVEST CODLING MOTH (LEPIDOPTERA: TORTRICIDAE) CONTROL OF FRESH APPLES (MALUS DOMESTICA BORKH.)

A radio frequency (RF) treatment, with a pulse mode to increase heating uniformity, was examined as a potential quarantine treatment against fifth instars of the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), in apples, Malus sylvestris L. var. domestica (Borkh.) Mansf., intended for export to Japan. Apples were exposed in water baths to 27.12‐MHz RF energy at 12 kW with a pulse mode of 30 s‐on/30 s‐off for different durations. The temperature uniformity was determined by measurements at 12 sites evenly spaced at two depths in the fruit. The most promising exposure time was 29 min. The efficacy of the treatment with the pulse mode was examined against the codling moth larvae by using exposures between 27 and 30 min and up to 30 min of holding time in bath after treatment. The treatment that killed all larvae with the least amount of energy was the 29‐min exposure with 50‐min holding time. This treatment was appraised for fruit quality in “Delicious” apples. Some injury was observed when treated fruits were removed from 1C storage after 30 days. When these fruits were held at 25C for 1 week, all were too damaged to evaluate for fruit quality. Although pulse mode increased heating uniformity in the fruit, the thermal requirements to control codling moth larvae may exceed the injury threshold of the fruits.     

BEHAVIOR OF STAPHYLOCOCCUS AUREUS IN SUCUK WITH NETTLE (URTICA DIOICA L.)

The behavior of Staphylococcus aureus was studied in sucuk (Turkish dry fermented sausage) with different levels of nettle (Urtica dioica L.). Sucuk batters containing different levels (1, 3 and 5%) of nettle were prepared and contaminated with S. aureus at approximately 10⁴ cfu/g. Sucuk batter not inoculated with S. aureus and not containing nettle addition was set as the control lot. Lactobacillus sakei Lb 706 was used as a starter culture. During ripening period, S. aureus, Micrococcus/Staphylococcus and lactic acid bacteria counts were determined. pH and water activity (a_w) values were also analyzed. The S. aureus count was under detectable levels in the control lot, and the pH level dropped below 5.0 after the first 24 h of fermentation. Initial pH values increased gradually in all three lots (1, 3 and 5%). At the end of the first 24 h of fermentation, a significant increase in S. aureus counts was determined in all lots of sausage except for the control lot. The pH value of the sucuk sample containing 1% nettle was under 5.0 on the second day. However, pH values for sucuk samples containing 3 and 5% nettle did not drop below 5.0 during the ripening period, including the fermentation phase. Nettle usage had no effect on the lactic acid bacteria count; however, it had significant effects on the Micrococcus/Staphylococcus count and a_w value.     

EFFECTS OF DIETARY CABBAGE (BRASSICA OLERACEA L.) ON THE TUMORIGENICITY OF 1, 2-DIMETHYLHYDRAZINE IN MICE

Diets containing dehydrated cabbage (Brassica oleracea L.) were fed to weanling male C57 BL/6 mice for nine months. Diets known to be adequate in all nutrients for mice were modified to include ground dehydrated cabbage leaves to 0, 10, 20, and 40% of their diet while holding protein, crude fiber, and lipid at constant levels. The animals were subcutaneously injected with 20 mg of 1, 2-dimethylhydrazine (DMH) per kg body weight at weekly intervals for 36 weeks. The DMH carcino-genicity varied with the proportion of cabbage in the diet and the tissue. Diets containing 10 and 20% cabbage enhanced DMH tumorigenicity while cabbage at 40% provided a protective effect. Tumors on the spermatic cord were the most predominant with occasional occurrence of kidney and liver tumors. Tumorigenicity is discussed in terms of two hepatic enzymes, cytochrome p-450 and p-nitroanisole-o-demethylase.