The effect of sub-zero temperatures on different lifestages of Lasioderma serricorne (F.) and Ephestia elutella (Hübner)

The effect of sub-zero temperatures on different lifestages of Lasioderma serricorne and Ephestia elutella was investigated as a means of disinfesting stored tobacco. Eggs, unacclimated cocoons and acclimated cocoons of L. serricorne were exposed to −10 °C, −15 °C and −20 °C in insulated boxes. There was no adult emergence from eggs or unacclimated cocoons following exposure to the respective temperatures for 4 h, 2 h and 1 h. With acclimated cocoons there was no adult emergence after 2 h at −15 °C and 1 h at −20 °C, but at −10 °C, there was adult emergence after 8, 12 and 24 h exposures.In field-scale experiments, cold acclimated fourth-instar larvae of L. serricorne were inserted into cases of leaf tobacco and boxes of finished product, put into commercial freezers and exposed to minimum temperatures of −10 °C, −18 °C or −25 °C. Critical temperatures were measured at the core of the commodity. No adults emerged from the commodity when exposed to at least −18 °C for periods ranging between 3.75 h and 39.25 h or when exposed to at least −25 °C for between 2.4 h and 3.7 h. At a minimum of −10 °C, 3 live adults emerged after 24 h exposure.With E. elutella, diapausing larvae were inserted into small scale tobacco bales and exposed to −10 °C, −13 °C, −15 °C or −20 °C. No emergence of adults and no larval survival was achieved after 21 d, 3 d and 2 h exposure at −10 °C, −15 °C and −20 °C respectively. At −13 °C, there was no adult emergence after 2 and 5 d exposure, but live larvae remained after 24 weeks incubation at 25 °C.Minimum conditions of −18 °C for 24 h and −25 °C for 4 h are recommended for the control of L. serricorne and −20 °C for 24 h for the control of E. elutella in stored tobacco (to fit with operational logistics).     

Effects of Whey Permeate-Based Medium on the Proximate Composition of Lentinus edodes in the Submerged Culture

ABSTRACT:  Biomass production, crude water-soluble polysaccharide (WSP), ash content, mineral profile, and crude protein content were determined for Lentinus edodes mycelia grown on whey permeate (WP)-based medium with lactose content of 4.5% or defined synthetic medium, and harvested after 5, 10, 15, or 20 d of fermentation at 25 °C. Harvesting time and the type of media interact to alter the chemical content of mycelia. Mycelia grown in WP had greater ( P < 0.05) WSP and ash than mycelia grown in the synthetic media. A maximum production of WSP was obtained on the 10th day (4.1 × 10²± 71 mg WSP/g dried mycelia) from mycelia grown on the WP-based media. Mycelia grown on WP harvested on the 20th day had the highest value in ash content (18 ± 3%). Potassium was found to be the main constituent in the ash of mushroom mycelia, which was followed by phosphorus, sodium, calcium, and magnesium. A steady increase of ash content was only noted in mycelia grown on WP. The calcium content of WP-grown mycelia was at least 10 times higher compared to mycelia grown in the control media regardless the harvesting time. Data in this research suggested that WP was more favorable than the synthetic media in the production of WSP, which is traditionally known for their medicinal value in L. edodes .     

DETERMINATION OF GLASS TRANSITION TEMPERATURE OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) AND EFFECTS OF VARIOUS CRYOPROTECTIVE BIOPOLYMER BLENDS ON SOME CHEMICAL CHANGES

Sucrose  +  sorbitol  +  gum arabic (2  +  2  +  0.15%), sucrose  +  sorbitol  +  carrageenan (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%), sorbitol  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%) and sorbitol  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%) were blended with ground rainbow trout and stored at glass transition temperature ( T _g) of rainbow trout ( − 13C), determined by differential scanning calorimetry at − 9 and − 18C for 6 months. Total volatile basic nitrogen (TVB-N) and thiobarbituric acid-reactive substances (TBARS) were determined at 1st, 3rd and 6th months of storage periods. Biopolymer blends and storage period had a significant effect ( P <  0.05) on the TVB-N and TBARS values. T _g and − 18C showed same effect on TVB-N and TBARS values but − 9C has statistically different effect on them.

PRACTICAL APPLICATIONS

The T_g value was found as −13C for rainbow trout. This value is higher than commercial storage temperature (−18C). This has a great importance in terms of economical viewpoint. It was determined that TVB-N values were same and TBARS values were similar at the end of 6 months storage at T_g and −18C. When considering these two parameters, it can be accepted that −13C could be an indicator of usability instead of −18C.     

ANTIOXIDANT PROPERTIES OF COCOA POWDER

This study was aimed to determine antioxidant properties of cocoa powder. Crude cocoa extracts were fractionated using prepacked column (25 cm  ×  2.0 cm) with Sephadex LH 20 and an increase in water–acetone (85:15, 70:30, and 40:60, v/v) as elution. The resulting fractions 1 (F1), 2 (F2) and 3 (F3) were tested for phenolic contents, antioxidant capacity, identification of bioactive compounds liquid chromatography-mass spectrometry (LC-MS) and stability test. Theobromine and caffeine were major compounds detected in F1 and F2. Monomer, dimer and trimer were identified in F3 as m/z 289, 578 and 867, respectively. Addition of F1 and F2 could reduce antioxidant capacity of F3. Catechin and epicatechin in F3 was stable when stored at 4 and −20C for 5 months. High antioxidant capacity in F3 was likely due to the monomeric, dimeric and trimeric phenolic compounds. The presence of methylxanthines could reduce antioxidant capacity of flavonoids in cocoa powder.

PRACTICAL APPLICATIONS

Numerous studies have been reported on the health benefits of cocoa powder. Polyphenol compounds present in cocoa powder could significantly contribute to their health-promoting activities. The study of bioactive compounds (polyphenols and methylxanthines) toward antioxidant capacity could reveal their actual antioxidant properties. Stability of individual polyphenol compounds under different storage condition and time could help in preserving their quality when producing products from cocoa powder.     

SHELF-LIFE DETERMINATION OF PRECOOKED FROZEN PORK MEAT PATTIES AT VARIOUS TEMPERATURES

Precooked frozen pork patties sampled from the same lot were stored at −10, −15 and −20C after vacuum packing in PE bags for the determination of shelf -life. The patties were sampled 10–13 times at 3–4 week intervals and were subjected to the determination of volatile basic nitrogen (VBN), peroxide value (POV), thiobarbituric acid reactive substances (TBA), surface color and texture after thawing at 5C for 15 h. Results from the triangle test were used to determine high quality life (HQL), and the scoring test and the quality index were used to determine practical quality life (PQL). The test results showed that VBN, TBA and POV in the samples increased as the storage period was extended. It was noted that color of samples became darker during the storage as indicated by the decrease in L value from 63.7 to 59.2. In addition, the shear force of the stored samples increased from 3.2 to 5.5 psi during the storage period. HQL of the meat patties were 147, 168 and 196 days, and the PQL 189, 224 and 252 days at −10, −15 and −20C, respectively. Statistical analysis of test results indicated that there were significant relationships between sensory scores and VBN, TBARS and POV of the stored patties (P<0.05). VBN was selected as the most reliable objective quality index for the shelf-life determination (PQL) of the precooked frozen meat patties, and PQL estimates based on VBN were close to those determined based on the sensory tests.     

Antioxidant capacity, phenolic content, and polysaccharide content of Lentinus edodes grown in whey permeate-based submerged culture

ABSTRACT:  Total antioxidant capacity (TAC), phenolic content, and crude water-soluble polysaccharide (WSP) were determined for Lentinus edodes mycelia grown on both whey permeate (WP)-based medium with lactose content of 4.5% and controlled medium, and harvested after 5, 10, 15, or 20 d of fermentation at 25 °C. Both methanol extracts and water extracts of L. edodes in this study were found to exhibit high free radical scavenging capacity. The harvesting time was found to contribute to most of the variability in the free radical scavenging capacity. High levels of antioxidant capacities (0.28 ± 0.03 and 0.29 ± 0.06 mmol TAE/g dry weight for methanol and water extracts, respectively) were observed in mycelia grown on whey permeate and harvested on day 10. Harvesting time and the type of media can interact to alter the chemical content of mycelia. Mycelia grown in whey permeate had greater ( P < 0.05) WSP than mycelia grown in the synthetic media. High levels of WSP (4.1 × 10²± 71 mg polysaccharide/g dried mycelia) were found in mycelia grown in whey permeate and harvested on day 10. Whey permeate grown mycelia had phenolic compounds ranging from 4.2 ± 0.1 to 8.0 ± 0.8 mg GAE/g dried mycelia. The overall means of total phenolic contents of mycelia grown in whey permeate were 5.9 ± 0.5 and 6.2 ± 0.6 mg GAE/g dried mycelia for methanol and water extracts, respectively.     

Viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Egyptian soft cheeses and ice-cream

Changes occurring in the viability of Salmonella enterica subsp. enterica during the preparation and cold storage of Domiati cheese, Kariesh cheese and ice-cream were examined. A significant decrease in numbers was observed after whey drainage during the manufacture of Domiati cheese, but Salmonella remained viable for 13 weeks in cheeses prepared from milks with between 60 and 100 g/L NaCl; the viability declined in Domiati cheese made from highly salted milk during the later stages of storage. The method of coagulation used in the preparation of Kariesh cheese affected the survival time of the pathogen, and it varied from 2 to 3 weeks in cheeses made with a slow-acid coagulation method to 4–5 weeks for an acid-rennet coagulation method. This difference was attributed to the higher salt-in-moisture levels and lower pH values of Kariesh cheese prepared by the slow-acid coagulation method. A slight decrease in the numbers of Salmonella resulted from ageing ice-cream mix for 24 h at 0°C, but a greater reduction was evident after one day of frozen storage at −20°C. The pathogen survived further frozen storage for four months without any substantial change in numbers.     

EFFECT OF DIFFERENT STORAGE CONDITIONS ON THE LIPID FRACTION OF A VEGETABLE CREAM

Fatty acids (free and esterified), diglycerides, peroxides and total sterols were determined in a vegetable cream. Cream samples were analyzed when fresh and after storage for 3 and 6 months at 4, 15, 30C and room temperature (10–25C). The product showed a higher amount of unsaturated fatty acids ( ≈ 50% of total fatty acids) with respect to milk fat and a low level of cholesterol ( < 0.01%). The phytosterol content ( ≈ 14 mg/100 g of cream) was not high enough to contribute to a decrease in cholesterolemia. Lipid oxidation remained low during storage (peroxides: 2.0–3.0 meq O₂/kg of fat), but a small increase was observed at room temperature after 6 months (about 6.0 meq O₂/kg of fat). Free fatty acids never exceeded 0.3% of fat. Storage at 4C and 15C delayed lipolysis in comparison to storage at 30C and room temperature.

PRACTICAL APPLICATIONS

The analysis of a vegetable cream demonstrated that it was a shelf-stable product, showing a high stability toward lipid oxidation and lipolysis. Such a product might be employed as vehicle for healthy fat compounds like long-chain polyunsaturated fatty acids, phytosterols and fat-soluble vitamins.     

MAINTAINING THE STORAGE QUALITY OF TROPICAL DRIED FRUIT MIX WITH GLYCEROL

Tropical dried fruit-mix was prepared from pineapple, papaya and banana. Pineapple and papaya cubes were prepared by soaking in a 60% sugar solution containing 0.4% sodium metabisulfite and glycerol at 0, 15 and 20%. Banana cubes were treated with 0.4% potassium sorbate solution containing 0, 15 and 20% glycerol without sugar. The fruit cubes were oven-dried at 65–75°C for 5–10 h and the dried fruits were mixed at a ratio of 1:1:1 (pineapple: papaya: banana). A 300 g sample of the mixture was packed in polypropylene bags (0. 04 mm) and stored at room temperature in cardboard boxes for a year. The glycerol-treated fruit-mix had higher moisture content but lower water activity than the control. Glycerol treatment improved the color of tropical dried fruit-mix. During storage, the color of glycerol-treated banana darkened whereas glycerol-treated papaya became lighter and more red than the control. The glycerol-treated fruit-mix, which retained more sulfur dioxide during storage, contained lower mold and bacterial counts. Use of 15 or 20% glycerol resulted in better color, texture, flavor and appearance of fruit mixture than the control samples.     

Microbial growth and colour of minimally processed shiitake mushroom stored at different temperatures

The effect of storage temperature on the microbiological and sensory characteristics of minimally processed shiitake was investigated. Shiitake mushrooms were washed, sanitised, packed in polystyrene trays, overwrapped with plastic film and stored at 7, 10 or 15 °C. Microbial counts, polyphenoloxidase activity, external lightness ( L* ) and acceptance tests were conducted. Mesophilic, aerobic psychrotrophic bacteria, yeasts and moulds predominated during storage. Pseudomonas was detected after 10 days' storage showing an increase of, approximately, 7 log cycles at 15 °C. Mushroom rejection occurred when the microbial population was lower than 10⁶ CFU g⁻¹, suggesting that, other factors, such as browning, affect mushroom spoilage more than microbial activity. Mushrooms treated with citric or ascorbic acids maintained high L * value during 10 days. The shelf life of minimally processed shiitake mushrooms was 10 days at 7 °C, but less than 5 days at 10 °C, and approximately 3 days at 15 °C.     

Optimization of the Freezing Conditions on Mackerel and Amberfish for Manufacturing Minced Fish

Optimal freezing, frozen storage and thawing conditions in preserving mackerel and amberfish for producing minced fish products were investigated. Based on assessments of extractability of 0.6M KCl-soluble proteins and actomyosin, Ca-ATPase activity of actomyosin, and gel-forming ability of kamaboko (kind of minced fish meat product), semi-dressed, dressed, and filleted samples showed stable and good quality of gel-forming ability during 3 months storage at −20°C. Optimal ultimate freezing temperatures of mackerel and amberfish were −20°C and between −30°C and −40°C, respectively. The optimal storage temperatures for mackerel and amberfish were −20°C and −40°C, respectively. Appropriate thawing methods for frozen mackerel were microwave and 20°C running water defrosting, while those for frozen amberfish were microwave, 20°C running water, and room temperature defrosting.     

CHANGES IN QUALITY DURING STORAGE OF VACUUM-PACKED SEA BASS (DICENTRARCHUS LABRAX, Linnaeus, 1758) COOKED BY DIFFERENT METHODS

This work evaluates the chemical, microbiological and sensorial characteristics of vacuum-packed sea bass processed by different cooking methods under different time/temperature conditions and storage at 2C. The heat treatments applied in core were: 5 min, at 180C for frying, 30 mi, at 230C for baking, and 16 min at 2450 MHz for microwave cooking. Chemical, microbiological and sensory quality changes were investigated periodically. In all groups; the total viable and psycrophilic bacteria counts increased throughout the storage period of vacuum-packed sea bass. Total viable counts of fried, baked and microwave-cooked sea bass reached 6.06, 7.00, 7.24 log cfu/g, respectively, after 15 days. On day 15, the total volatile base nitrogen (TVB-N) value of microwave-cooked sea bass exceeded the allowable limit of 38.72 mg/100 g, whereas the TVB-N value of fried and baked sea bass reached 22.46 and 29.85 mg/100 g, respectively. Therefore, it can be concluded that frying at 180C for 5 min in core is the most effective cooking method to ensure the safety and extend the shelf life of fried sea bass, preserving its microbiological guality.

PRACTICAL APPLICATION

This study establishes the chemical, microbiological and sensory quality of vacuum-packed sea bass and emphasizes the relevance of the quality changes of the different cooked sea bass. Heat treatments and storage temperatures are very important to ensure the safety of the fish product.     

Super Chilling Enhances Preservation of the Freshness of Salted Egg Yolk During Long-Term Storage

ABSTRACT:  Pasteurized egg yolk with 10% (w/w) salt was stored at 5, –5, –15, –20, and –30 °C for 1 to 6 mo, respectively. Changes in generation of volatiles of the stored samples (5 and −5 °C for 6 mo) were analyzed by SPME-GC-MS. Emulsifying properties of egg yolk stored at −5, −15, −20, and −30 °C for 1 mo, respectively, were also evaluated by measurement of emulsion particle diameters in model emulsions prepared with the yolk samples. In addition, structural changes in low-density lipoprotein (LDL) in the egg yolks dependent on storage conditions for 6 mo were evaluated by ³¹P–NMR. Volatile compounds such as hexanal, 2-methylbutanal, and 3-methylbutanal increased in egg yolk during storage at 5 °C; however, volatile compounds hardly increased in any samples stored at −5 °C (super chilling). The mean emulsion particle diameter in super chilled egg yolk was significantly smaller than that in egg yolk stored at the other lower temperatures. In addition, the results of ³¹P–NMR evaluation suggested that prevention of structural changes of LDL resulted in maintenance of emulsifying properties of egg yolk. Thus, these results indicate that super chilling is an effective means of preserving salted egg yolk during long-term storage.     

RHEOLOGICAL BEHAVIOR OF CONCENTRATED INULIN SOLUTION: INFLUENCE OF SOLUBLE SOLIDS CONCENTRATION AND TEMPERATURE

Inulin is a storage polysaccharide present in more than 30,000 vegetable products, including chicory roots, that are considered suitable for industrial application. The objective of this work was to evaluate the influence of temperature and the soluble solids concentration on the rheological behavior of a concentrated inulin solution obtained from a centrifugation process from chicory roots, after freezing at − 24C. For all the evaluated soluble solids concentrations, inulin solutions showed a rheological behavior of a highly pseudoplastic fluid, with high resistance to flow at low strain rates followed by a breakdown of the structure when the shear rate increased. The effect of temperature on the apparent viscosity of inulin solutions can be represented by the Arrhenius equation. The rheological behavior of inulin solutions can be represented by the Herschel–Bulkley, Casson, Cross and Power Law equations, where the consistency index increases as temperature rises and the soluble solids concentration as well.

PRACTICAL APPLICATIONS

The main objective of this work was to analyze the rheological behavior of a concentrated inulin solution obtained from chicory roots, to check the possibility of its application to obtain powder inulin.
The concentrated inulin solution was obtained by diffusion in hot water, followed by concentration by evaporation and phase separation conducted by lowering the temperature (−24C) and centrifugation at a velocity of 10,000 rpm for a time interval of 15 min. However, this solution is still going to be processed. Therefore, it is important to know its rheological behavior.
The influence of temperature and the soluble solids concentration on the rheological behavior of the concentrated inulin solution was also studied.     

CONVECTIVE DRYING OF PUMPKIN: INFLUENCE OF PRETREATMENT AND DRYING TEMPERATURE

The aim of this research was to study the influence of blanching as a pretreatment on the drying rate, color and rehydration rate of pumpkin slices ( Cucurbita maxima ) dried in a convective dryer at 50, 60 and 70C.
The different pretreatments did not modify drying time. The diffusion coefficient depended on temperature and moisture content, but not on pretreatments. It varied between 1.6 and 2.9  ×  10⁻⁹ m²/s and activation energy was approximately 35.6 kJ/mol. The rehydration rate of the dried sample, which was found to be influenced by drying temperature but not by the pretreatments, reached about 2 kg water/kg dry solid in about 150 s in boiling water. Color parameters " L " and " b " were influenced by drying temperature and pretreatments. Parameter L varied between 36 and 53 and parameter b varied between 20 and 31. Samples dried at 70C without pretreatments presented color parameter values very similar to those of the fresh sample.

PRACTICAL APPLICATIONS

This work evaluates the pretreatment and drying conditions of pumpkin. Five parameters of the optimal product are considered: pretreatment time, drying time, temperature, color and rehydration rate of the product. With these results, drying of pumpkin can be carried out in industrial convective dryers and the dried product may be used in the preparation of soups, premixed foods, snacks, etc.     

Novel microwave–freeze drying of onion slices

The present study aimed to introduce the capability of a novel dehydration technique. To do so, slices with various thicknesses (3.5 and 7 mm) of white onions were dried using commercial freeze drier (abs. pressure 0.005 mbar, temp. 45 °C), our own designed microwave-vacuum drier (abs. pressure down to 300 mbar) under various microwave powers (120–1200 W) and microwave-vacuum–freeze drier (onion slices kept at −20 °C for 2 h). Then, their dehydration rates and some quality parameters, such as rehydration ratio, colour ( L*, a* and b* ) and micro-structure were investigated. Our findings showed that microwave-vacuum–freeze drier is practically a rapid, simple, efficient, economic and novel dehydration technique which can be used for dehydration of mainly foodstuffs. The quality properties of slices produced by this novel method were also completely comparable and competitive with commercial freeze drier with over 96% saving on processing time and enormous amount on energy and capital investments.     

Application of competitive indirect enzyme-linked immunosorbent assay (Ci-ELISA) for monitoring the degree of frozen denaturation of bovine myosin

The denaturation of myosin on freezing and frozen storage was monitored using competitive indirect enzyme-linked immunosorbent assay (Ci-ELISA) formatted with polyclonal antibodies anti-MWM IgG, anti-S-1 IgG and anti-LMM IgG raised against the antigens (Ags) bovine myosin whole molecules (MWMs), heavy meromyosin S-1 (myosin head part, S-1) and light meromyosin (myosin tail part, LMM) respectively. Beef slices and cuts stored at −20 °C or −50 °C lost immune affinity with all antibodies, in particular anti-LMM IgG. Repeated thawing–refreezing treatment caused more myosin denaturation than simple freezing. Myosin from beef stored at −20 °C was denatured more than that stored at −50 °C. The immune affinities between anti-LMM IgG and thawed samples were similar to those from anti-MWM IgG. We were unable to differentiate reliably between fresh and thawed beef using anti-S-1 IgG. Myosin was denatured by freezing, in particular its tail part (LMM).     

Development of a mushroom-whey soup powder

Summary Mushroom‐whey soup powder was prepared by cooking mushroom with concentrated cheese whey and blending. The seasonings (onion, garlic and ginger) were fried separately in hydrogenated fat, and cornflour was added if thickening was desirable. After the addition of salt and a further quantity of concentrated whey, the soup mix was again blended. It was then spray‐dried to produce a mushroom‐whey soup powder. The physico‐chemical properties of the soup powder, such as moisture content, loose and packed bulk density, wettability, insolubility index, thiobarbituric acid and hydroxy methyl furfural content, increased during storage. However, dispersibility and reflectance value decreased during storage. The soup powder reconstituted well when boiled in water for 2 min. The reconstituted soup was considered acceptable, with an overall acceptability score of 7.1 on a nine‐point hedonic scale, after 8 months of storage of the soup powder at 30 °C when packed in metalized polyester.     

SURVIVAL OF ESCHERICHIA COLI, STAPHYLOCOCCUS AUREUS AND SALMONELLA ENTERITIDIS IN FROZEN CHICKEN HAMBURGER

The survival of food pathogens during frozen storage of chicken hamburgers was evaluated. Hamburgers were contaminated with Escherichia coli (ECHC), Staphylococcus aureus (SAFH) and Salmonella Enteritidis (SE86), separately, and stored at −18C for 28 days. Results demonstrated reductions of 0.63 log₁₀ cfu/g, 0.73 log₁₀ cfu/g and 0.27 log₁₀ most probable number/g in the populations of ECHC, SAFH and SE86, respectively. These microorganisms were also stored at −18C in 0.1% peptone water and presented significantly different reductions ( P <  0.05) when compared with frozen hamburgers, suggesting that components of chicken hamburger may exert a cryoprotective effect on microbial cells.

PRACTICAL APPLICATIONS

Even though Brazilian poultry meat industries present high levels of quality control, the presence of bacterial pathogens in hamburgers may occur. In Brazil, chicken hamburgers are frequently commercialized frozen, and it is well established that frozen temperatures are able to avoid microbial growth. However, frozen temperatures can also be able to inactivate part of the bacterial population, and the magnitude of its effect will vary according to the type of food and the process that it was submitted. This study evaluated the survival of Escherichia coli , Staphylococcus aureus , and Salmonella Enteritidis in frozen hamburgers, aiming to verify if this process could provide an additional margin of safety to this product.     

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