STORAGE BEHAVIOR of an EARLY GARLIC (ALLIUM SATIVUM L.) SUBJECT to GAMMA-RAY RADIOINHIBITION

Garlic bulbs of an early cultivar (Rosado Paraguayo) were irradiated with a dose of 50 Gy of Co-60 gamma rays at 30 days after harvest. Experimental lots were stored up to 300 days in a commercial warehouse (6-32°C; R.H. 40-50%). the treatment reduced the weight loss of the bulbs and increased the percentage of both marketable bulbs and cloves without affecting organoleptic properties. the results show that both the raw/fresh market for this early cultivar and the garlic processing industry would profit from the radioinhibition process.     

Effects of Irradiation and Storage on the Flavor of Garlic Bulbs cv "Red"

The effects of 50 Gy gamma irradiation 30 days after harvest on the flavor of garlic bulbs cv “Red” during storage at room temperature for 300 days were evaluated. The contents of sulfur compounds and enzymatic pyruvate (EP) were determined by GLC and spectrophotometry as a measure of flavor intensity. Upon comparison of irradiated and nonirradiated bulbs no differences were observed in the contents of EP, cyclic disulfide compounds 144-1 + 144-11 (GLC-induced rearrangment products of allicin, the chief flavor component), and diallyl disulfide (DADS). At the end of the storage both samples showed a significant reduction in 144-1 + 144-11 and EP. On the contrary, DADS underwent an increase in both treatments.     

Physio-chemical behavior of γ-irradiated garlic bulbs under ambient storage conditions

The present study was undertaken to study the effect of different gamma irradiation doses on storage life of garlic bulbs under ambient storage conditions. Garlic bulbs (cv. PG-18) were irradiated with gamma rays in dose range of 0–0.2 kGy and stored under ambient conditions (Temp 27–35 °C and RH 34–76%). Physical and chemical quality parameters i.e. physiological loss in weight (plw), rotting, sprouting, total soluble solids, firmness, ascorbic acid and allicin content of garlic bulbs was determined fortnightly to assess its storage life. On 195th day of ambient storage, the weight loss of bulbs ranged from 32.22 to 38.48% in all irradiation doses. It was observed that upto 30 days and 150 days, there was no rotting and sprouting, respectively in all the treatments. Firmness, total soluble solids, ascorbic acid and allicin content were significantly different with storage period and irradiation dose levels. It is concluded that garlic bulbs irradiated @ 0.12 kGy of gamma radiation resulted in minimum post-harvest losses along with maintaining their marketable shelf life for 4 months under ambient storage conditions.     

Effects of Irradiation on the Volatile Compounds of Garlic (Allium sativumL)

The effects of 0·15 kGy gamma irradiation on the content of volatile compounds in garlic bulbs during storage at room temperature were evaluated. The content of diallyl disulphide decreased immediately after irradiation. However, at the end of 8-month storage both irradiated and unirradiated samples showed a significant increase in diallyl disulphide.     

Improving fresh and processed garlic by irradiation under different storage conditions

Hungarian garlic bulbs were irradiated with gamma rays (0.15 kGy) and stored at 20, 4 and ?20 °C for 8 months. At the end of storage period, marketable value of bulbs increased especially with those kept under low temperatures, whereas the storage at room temperature (20 °C) produced high losses in bulbs due to infestation and/or infection in unirradiated but less in irradiated samples. Gas chromatographic analysis of volatile oils revealed the presence of 18 compounds. Diallyl disulphide and diallyl trisulphide compounds were cleary identified. Irradiation induced reduction in the percentages of these compounds especially for the first one. Cold or freezing treatment preserved the volatile sulphur contents on garlic cloves at their maximum value. Also, subsequently drying of irradiated cloves resulted in better quality than those unirradiated before drying process. It is concluded that irradiation as an alternative preservation method is useful in the improvement of storeability of fresh or dried garlic bulbs during long storage period.     

SENSORY QUALITY of IRRADIATED ONION and GARLIC BULBS

The radioinhibition process has shown to prolong shelf-life of "Valenciana sintética 14" onion variety and "Colorado" garlic variety. Sensory attributes of the irradiated bulbs were tested monthly by trained judges during extended storage in warehouse conditions (6-32C, R.H. 40–50%). the sensory properties observed were external and internal appearance, firmness and odor.
The irradiated bulbs were judged to be superior in quality with respect to internal and external appearance (p < 0.01) and firmness (p < 0.01), after 180 days postharvest. the irradiated bulbs showed no difference in odor (p < 0.05), when compared to unirradiated ones, through the storage period.     

赤豆辐照保藏研究

辐照处理日期的早晚对赤豆防虫保鲜的效果有明显影响。收获后当年11月份辐照的赤豆,只需0.5万拉德就可以安全地贮藏一年而不出虫。在同样的剂量下,剂量率高的杀虫效果要优于剂量率低的。在50万拉德内,辐照对赤豆营养成分的影响可以忽略。辐照赤豆贮藏一年后品质仍然良好。感官评定和色谱—质谱分析表明,辐照赤豆与未辐照赤豆之间的差别是不显著的。     

The Effect of Gamma Irradiation as a Phytosanitary Treatment on Physicochemical and Sensory Properties of Bartlett Pears

A major concern in exporting agricultural commodities is the introduction or spread of exotic quarantine pests to the new area. To prevent spread of insect pests, various phytosanitary measures are used. Worldwide commercial use of irradiation as a phytosanitary treatment has increased greatly in recent years; however, trade has been limited to tropical fruits. Bartlett pear is a major summer variety of California pears with great potential and market for export. In this study, the effect of gamma irradiation at dose levels of 400, 600, and 800 Gy on physicochemical properties and sensory attributes of early and late harvest Bartlett pears was investigated. Firmness and color changes indicate that irradiation delayed the ripening of pears by 1 d. For the early harvest pears, scarring, bruising, and off flavor were significantly increased at the highest irradiation dose (800 Gy). The appearance of early harvest 800 Gy irradiated pears was the only attribute that received significantly (P ≤ 0.05) lower scores than the control in consumer testing. For the late harvest pears, the 400 Gy fruit had lowest levels of scarring and bruising as rated by trained panelist but consumers did not score the control and 800 Gy fruit differently for any attribute. Titratable acidity, total soluble solids, and chroma were significantly (P ≤ 0.05) decreased and hue increased by irradiation for the early harvest pears. These results suggest that there was a difference in radiotolerance of early and late harvest pears, but in both cases, irradiation at 400 to 600 Gy seemed to maintain best quality.     

Evaluation of ethereal extracts of irradiated garlic

The present work describes the results of a comparative study on ethereal extracts of ‘red’ garlic bulbs, both in control samples and samples irradiated with 50 Gy of ⁶⁰Co gamma rays for sprout inhibition. The evaluations were carried out by both gas-liquid chromatography and visible and infra-red spectroscopy.During 180 days' storage post-treatment in a commercial warehouse (Temperature: 6–32°C, RH: 58–86%) no appreciable changes were detected in gas-liquid chromatograms between control and irradiated samples. Neither were any differences in spectral character in the visible and infra-red ranges observed between the two types of samples maintained under similar storage conditions for 90 days after irradiation.     

高能电子束与60Coγ射线对大蒜辐照保鲜效果的比较研究

我国大蒜辐照抑芽工艺规范没有对60Coγ射线和电子束应用的工艺参数做出区分,为明确两者对大蒜抑芽保鲜效果的差异,以60Co 产生的γ射线和电子加速器产生的高能电子束,分别对大蒜进行辐照处理,辐照剂量为200、500、800Gy,辐照后置于室温(5～25℃,RH 70%～85%)贮藏,并对贮藏期间大蒜内芽生长情况及各生理指标进行测定。结果表明：两种辐照源均能有效抑芽,且相同辐照剂量下,电子束辐照抑芽效果强于60Coγ射线;200Gy 和500Gy 的两种辐照均能抑制大蒜呼吸作用,延缓质量损失,且对大蒜鳞茎外皮颜色和大蒜风味品质影响不大;而高剂量800Gy 的两种辐照则刺激大蒜呼吸增强,失重率升高,大蒜干缩严重。从大蒜营养品质和商业品质的角度综合分析,电子束采用200Gy、60Coγ射线采用500Gy 对大蒜的抑芽保鲜效果较好。     

Irradiation Effect on Onion Keeping-Quality After Sea-Shipment from Argentina to the Netherlands

Onion losses occur due to sprouting and rot. Onion cultivar Valenciana was irradiated with 60 Gy, shipped from Argentina to the Netherlands, and stored 6 months at 4°C. The rot in unirradiated samples increased after 4 months while rot in irradiated samples remained almost constant. Irradiation almost completely prevented sprouting. Storage losses were 50% for unirradiated and 20% for irradiated samples. Irradiated samples showed an improvement in general appearance. Irradiation reduced weight loss and damaged bulbs were more susceptible to storage rot.     

Suitability of Dukat strawberries for studying effects on shelf life of irradiation combined with cold storage

A new Dukat variety of strawberries was used to study the effect of irradiation combined with cold storage on their shelf life and chemical composition. Strawberries, with or without stems, were irradiated with a dose of 2.5 or 3.0 kGy within 6-10 or 20-24 h after harvesting. Results of the sensory evaluation showed that the minimum storage time for the fruits could be extended by a minimum of 9 days. If the time between harvest and irradiation was shorter, better results for storage experiments were obtained. Fruits with stems were more suitable for cold storage after irradiation than those without stems. Irradiation of strawberries did not change the titratable acidity and content of the reducing sugars. Colour intensity and ascorbic acid levels decreased in proportion to the absorbed dose and storage time.     

Influence of competitive microbial flora and inoculum size of Penicillium purpurogenum on the production of rubratoxin-B in corn medium before and after exposure to gamma radiation

The influence of inoculum size on the production of rubratoxin-B by P. purpurogenum was estimated on unirradiated and irradiated corn stored for prolonged periods at 28 °C and at a moisture content of 25%. Irradiation at doses of 1.0–3.0 kGy reduced the level of mould growth greatly relative to unirradiated controls. Rubratoxin-B production in corn grains at all doses after 40 days was less than the unirradiated control level and was below the detection limit above 4.0 kGy. Non-sterile corn that was inoculated with conidia of the fungus and then irradiated with 2.0 kGy gamma rays, produced lower rubratoxin-B levels compared with unirradiated controls. When corn was inoculated with 10⁵ spores per gram after irradiation, the spore count and rubratoxin-B level were higher than the unirradiated control after 60 days. The total viable counts of endogenous fungal flora in the corn were reduced by the 2-kGy radiation dose, but after 20 days of incubation the numbers of P. purpurogenum increased with greater enhancement of rubratoxin-B production.     

Investigation of the volatile aroma components of garlic leaves essential oil. Possibility of utilization to enrich garlic bulb oil

The volatile aroma components of Egyptian green garlic leaves essential oil was investigated for the first time. After the utilization of garlic bulbs to prepare garlic oil or after drying the bulbs to produce garlic powder, garlic leaves are considered to be waste material, which is disposed of without any benefit. In this investigation, green garlic leaves were distilled and the essential oil was subjected to GC and GC-MS identification. The yield of the oil was 0.06% (based on wet weight of the leaves). The most prominent compounds of the essential oil were diallyl trisulfide (32.32%), followed by diallyl disulfide (31.35%) and methyl allyl trisulfide (11.40%); these compounds are the same as those found in garlic bulb oil. This means that garlic leaf oil is a rich, renewable and priceless source of garlic aroma compounds which could be utilized in fortification and enriching of garlic bulb essential oil to increase its quantity without changing the quality. Utilization of green garlic leaves for production of essential oil will also save, to some extent, the costs of disposing of large amounts of leaves in garlic possessing factories, transforming them into profits.     

Development, reproduction, and control of the Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), in stored seed garlic in Mexico

Developmental time, fecundity, and egg hatch rate were determined for the Indian meal moth, Plodia interpunctella (Hübner), reared on fresh garlic seed at room temperature in Mexico. Duration of the egg stage averaged 4.7±0.8 days with an egg hatch rate ranging from 82% to 95%. Five larval instars were determined based on head-capsule width. Total larval developmental time from egg hatch to adult emergence ranged from 42 to 47 days. Adult females began to oviposit within 12-48 h after mating with the maximum oviposition rate occurring during the first 24 h after mating. The mean (±SE) number of eggs laid by females was 212±34 with a range of 117-303. Application of pirimiphos-methyl, malathion, and permethrin to 30 kg lots of garlic seed failed to prevent infestation and bulb damage by the larvae. However, compared with controls, the percentage of damaged bulbs and the number of larvae detected during 12 weeks of storage was smaller on garlic treated with four doses of pirimiphos-methyl.     

INFLUENCE OF MOISTURE CONTENT AND STORAGE TEMPERATURE ON THE PRODUCTION OF AFLATOXIN BY ASPERGILLUS FLAVUS EA-81 IN MAIZE AFTER EXPOSURE TO GAMMA RADIATION

The effect of gamma radiation on aflatoxin production by Aspergillus flavus EA-81 in maize with different initial moisture levels was determined over a 15-day period. The viability of A. flavus on maize decreased over time with increasing moisture contents and storage at 8C. After 45 days at 28C, levels of viable conidiospores of A. flavus increased from 4.5 × 10⁷ to about 3.0 × 10⁸ per gram of maize. Levels of aflatoxin B₁ produced by A. flavus were 10 μg kg^-1 in the maize stored at 8C after 45 days. Production of aflatoxin was highest at 40% moisture and 28C. Irradiation of 1.0 or 2.0 kGy greatly reduced the level of mold growth relative to unirradiated controls. A dose of 4.0 kGy eliminated all viable fungi. Aflatoxin B₁ production decreased with increased levels of irradiation and was negligible at 4.0 kGy. When maize was inoculated after irradiation and stored, the spore counts and aflatoxin levels were higher than in unirradiated and inoculated controls after 30 days. Apparently, the natural competitive microflora prevented growth and thus limited higher concentrations of aflatoxin in maize.     

Use of esr spectroscopy for the detection of irradiated whiting (Merlangius merlangus)

Previously frozen whiting were thawed overnight and irradiated the following day with doses of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 kGy, with four replicates per treatment. Four unirradiated whiting were used as controls. The fins, scales and vertebrae were removed from each fish and freeze dried prior to determination of the free radical concentration using electron spin resonance spectroscopy. The spectra which were derived from each of the components could be used to qualitatively detect irradiation. The signal strength increased significantly with increasing irradiation dose for both the vertebrae and fins although the response was more significant for the vertebrae. Thus the technique has potential for the quantification of the irradiation dose received. A further 20 defrosted whiting were irradiated at 5 kGy and an additional four served as unirradiated controls. After irradiation, the samples were stored in four groups each containing one control and five irradiated samples and analysed after storage periods of 0, 7, 14 and 21 days at 3±1°C. This simulates normal storage conditions for fresh fish. The signal from irradiated, freeze dried, ground vertebrae did not change significantly as storage time increased.     

Role of precursors on greening in crushed garlic (Allium sativum) bulbs, and its control with freeze-dried onion powder

BACKGROUND: Lachrymatory factor (LF) synthase in onion bulbs reacts with S‐1‐propenyl‐L ‐cysteine sulfoxide (1‐PeCSO), a key compound in garlic greening. In this study, freeze‐dried onion powder containing LF synthase was used in treatments to control garlic greening. Prior to the use of freeze‐dried onion powder to treat greening garlic bulbs, model reactions were conducted to confirm the reactivity of 1‐PeCSO in onion bulbs to garlic greening. RESULTS: While pink pigments were generated from 1‐PeCSO, green pigments were produced from the combination of 1‐PeCSO and S‐2‐propenyl‐L ‐cysteine sulfoxide (2‐PeCSO). However, pigments were formed in the systems containing 1‐PeCSO, amino acid and alliinase. Even non‐greening garlic bulbs stored at 20 °C turned green with the reaction of 200 g L^?1 1‐PeCSO; therefore 1‐PeCSO isolated from onion bulbs had the same role as 1‐PeCSO in garlic bulbs in terms of greening. Onion bulbs turned green after the addition of 600 g L^?1 2‐PeCSO. The addition of freeze‐dried onion powder inhibited garlic greening, and treatment with 15 g kg^?1 onion powder gave the best storage stability of crushed garlic bulbs. CONCLUSION: The addition of freeze‐dried onion powder inhibited the greening in crushed garlic bulbs, and treatment with 15 g kg^?1 onion powder gave the best storage stability of crushed garlic bulbs. Copyright © 2011 Society of Chemical Industry     

Germination test for identification of irradiated garlic

Ionising radiation can be used to inhibit the sprouting of garlic. This study investigates whether a simple germination test can be used to detect irradiated garlic. The results show that the germination test can be used as a detection method for garlic irradiated in the dormancy period. Detection is even reliable for samples treated with 25 Gy. For garlic irradiated after the dormancy period the germination test does not function properly. However, in this case the sprout-inhibiting effect of irradiation is also inadequate. For some samples, standard detection methods such as thermoluminescence, electron spin resonance and photostimulated luminescence were also applied. Whereas thermoluminescence measurements unequivocally proved the radiation treatment, electron spin resonance and photostimulated luminescence were not conclusive.     

Synthesis and characterization of novel sulfur-containing 2-(1H-pyrrolyl) carboxylic acids and their effects on garlic greening

It has been established that protein amino acids are involved in garlic greening by reacting with thiosulfinates to form pigment precursors (PP), a class of 2-(1H-pyrrolyl) carboxylic acids. This opens an interesting question of whether specific sulfur-containing non-protein amino acids naturally occurring in garlic such as derivates of cysteine and their corresponding sulfoxides also play a role in garlic greening through the same way. To answer this question, four new sulfur-containing model compounds having a 2-(1H-pyrrolyl) carboxylic acid moiety were synthesized by reacting four non-protein amino acids with 2,5-dimethoxytetrathydrofuran, respectively, to study their effects on garlic greening, the structures of which are similar to that of a previously proposed pigment precursor for garlic greening. The puree of freshly harvested garlic bulbs turned green after being soaked in solutions of P-methyl, P-allyl and P-propyl, and with both increasing concentrations and incubation time, the green color of the puree became deeper. These results provide evidences that the sulfur-containing non-protein amino acids likewise participate in garlic greening by a similar pathway to their analogues, protein amino acids. Additionally, the three compounds exhibited a good relationship between structure and activity of garlic greening, namely, the larger the size of the R group, the larger the contribution. In contrast, P-methyl-O, P-methyl’s sulfoxide cannot turn the puree of freshly harvested garlic bulbs green within the 13 days time frame of the experiment under the same conditions.