Cold Storage Period Research Articles

Comparison of Ethylene Sensitivity of Three Tomato Cultivars From Different Tomato Types and Effects of Ethylene on Postharvest Performance

The aim of study was to investigate ethylene sensitivity of different types of tomatoes and the effects of ethylene on their postharvest performance. For that purpose, beefsteak, heirloom and cluster types of tomato fruit were harvested at the breaker maturity stage and divided into two groups one of which was treated with 150 μL L−1 ethylene and the other was untreated for comparison. Ethylene treated and untreated fruit were stored at 12 °C and 90+5% relative humidity for 35 days and subsamples removed every 7 days for postharvest quality analysis. After each removal time, fruit were kept at 20 °C for 3 days in order to determine shelf life performance. Ethylene treatment lead to increase respiration rate, ethylene production, weight loss but decreased fruit firmness in all tested tomato cultivars. Minimum ethylene production and respiration rate occurred in untreated beefsteak tomatoes. At the end of cold storage and shelf life period, the highest L* values and fruit firmness were recorded for control beefsteak tomatoes. The conclusion drawn from this experiment was that the cluster type of tomatoes was more sensitive, while beefsteak type of tomatoes was found to be less sensitive to ethylene treatment as they had the highest and lowest amount of ethylene productions respectively. Untreated beefsteak tomatoes exhibited maximal postharvest quality compared to other treatments after 35 days cold storage and shelf life.

Influence of pulsing and wet cold storage on the vase water microbial profiles and overall quality of cut gladioli

Abstract Occlusion of the stem vasculature by microorganisms that proliferate in the vase water, or the plant vessels, leads to water stress symptoms that reduce postharvest quality of cut flowers. This study aimed to determine the effects of pulsing and wet-cold storage on the microbial profiles in cut Gladiolus grandiflorus L. cv. Fado. Pulsing treatments of 600-ppm 8-hydroxyquinoline sulfate plus 5% sucrose solution versus distilled water were administered before wet cold storage periods of 0-5 days in cut Gladiolus, previously grown from corms under open field. A two-by-six factorial experiment embedded in a completely randomized design with four replicates was accomplished. Proc GLM in two-way Anova was adopted, and the means were separated using Tukey’s test at a 5% level of significance. The pulsing treatment of 600 ppm 8-HQS plus 5% sucrose, the wet cold storage duration and their interactive effects significantly (P˂0.0209; ˂0.0001 and ˂0.0001 respectively) affected the means of the colony-forming units in the vase water of cut Gladiolus at senescence. The prolonged vase life of cut gladioli spikes was associated with decreased microbial proliferation as influenced by pulsing and wet storage duration of up to 4 days. Data generated from this study will improve existing technologies related to the quality and market value of this Gladiolus cultivar.

Effects of Cold Storage on Host Antheraea pernyi Egg Quality for the Egg Parasitoid Anastatus fulloi Sheng and Wang.

Simple SummaryProducing and field releasing a large number of natural enemies within a short time for pest control helps biological control programs succeed. However, host eggs are often unsynchronized with pest occurrence. Storing host eggs can help synchronize the production of parasitoids with demands of the program. Anastatus fulloi is an egg parasitoid wasp that has been successfully used to control the Tessaratoma papillosa Drury populations in south China. Antheraea pernyi eggs are used as factitious hosts of Anastatus fulloi, and cold storage of these eggs is important for large-scale rearing and successful release of Anastatus in the field. We studied the effects of cold storage of A. pernyi eggs on host egg quality and the fitness of A. fulloi. Cold storage reduced host egg quality and the suitability of host eggs for A. fulloi. To minimize losses in the large-scale rearing of A. fulloi, A. pernyi eggs should be refrigerated in a 0–3 °C or −5 °C water bath. The storage period should not exceed 6 months. The results of this study provide technical support for mass rearing of A. fulloi in biological control programs.Chinese silkworm (Antheraea pernyi) eggs are used as factitious hosts of Anastatus fulloi, and refrigeration of these eggs is essential for large-scale rearing of A. fulloi. We studied the effects of cold storage of A. pernyi eggs on egg quality and the fitness of A. fulloi reared on the eggs. Four cold storage treatments and two cold storage periods were assessed. The 0–3 °C refrigerator treatment was unsuitable for long-term (>70 days) storage. Cold storage at −5 °C and −18 °C increased the loss rate of A. pernyi eggs, but there was no significant difference between the control and 0–3 °C water bath treatment. The parasitism rate of A. fulloi was reduced when A. pernyi eggs were refrigerated for 6 or 12 months. There were no obvious differences in eclosion rate and percentage of females between control and eggs subjected to 6-month storage in 0–3 °C, −5 °C, and −18 °C water bath treatments. However, the eclosion rate and percentage of females decreased sharply when the storage period was 12 months. The overall eclosion rate of A. fulloi was reduced at the prolonged refrigeration time. Cold storage reduced host egg quality and their fitness suitability for A. fulloi. To minimize losses in the large-scale rearing of A. fulloi, A. pernyi eggs should be refrigerated in a 0–3 °C or −5 °C water bath treatment, and the storage period should not exceed 6 months.

Effect of Supercritical Extract from Black Poplar and Basket Willow on the Quality of Natural and Probiotic Drinkable Yogurt.

Simple SummaryFermented milk products should be an important component of the human diet due to their high nutritional value and easy digestibility. In order to enhance the nutritional value of yogurts, additives in the form of plant-based raw materials are often used. Phytoextracts are a mixture of biologically active compounds that can have beneficial effects on the human body and influence both the manufacturing process and the quality of food products. The incorporation of extracts from the basket willow (Salix viminalis) into natural and probiotic yogurts reduced the fermentation time and increased their antioxidant activity. Sensory evaluation of the appearance and texture of yogurts enriched with extracts showed no significant differences compared to natural yogurts. The addition of plant extracts may enable the standardisation of yogurt quality and increase its biological activity.Yogurt is a fermented milk drink produced by Streptococcus thermophilus, Lactobacillus delbrüeckii ssp. bulgaricus, or Lactobacillus rhamnosus, which can be enriched with polyphenolic compounds to enhance its antioxidant properties. Supercritical (scCO2/H2O) extracts obtained from the mixture of bark and wood of black poplar (Populus nigra) and basket willow (Salix viminalis) are the source of bioactive compounds. The aim of the study was to assess the effect of supercritical extracts from the P. nigra and S. viminalis on the fermentation, quality, and bioactive properties of drinkable natural and probiotic yogurts. The incorporation of scCO2/H2O extracts at a dose of 0.01% (w/v) into milk for the production of natural and probiotic yogurts increases their functional properties by enhancing the antioxidant activity without causing negative effects on the physicochemical and organoleptic properties of products. The antioxidant activity of yogurt with scCO2/H2O extract from P. nigra and S. viminalis was higher than control yogurts by 1.3–13.2% and 4.4–37.5%, respectively. The addition of a supercritical S. viminalis extract reduced the time of natural and probiotic yogurt fermentation. Natural and probiotic yogurt with scCO2/H2O extracts added was characterised by a bacterial population size of over 7 log cfu/g, and the microflora was active throughout the cold storage period. FTIR analysis confirmed the presence of scCO2/H2O extracts from P. nigra or S. viminalis in both types of yogurt. A secondary structure analysis confirmed interactions between compounds of scCO2/H2O extract from P. nigra and S. viminalis extract with milk proteins. These interactions affect the compounds’ structural and functional properties by changing, e.g., their digestibility and antioxidant properties.

Improving hydration and vase life of cut Zinnia

Zinnia (Zinnia elegans Jacq.) is a commercially important species in the cut flower industry that has several postharvest challenges including hydration, cold storage, and seasonality. The purpose of this work was to increase vase life of cut zinnia by assessing hydration, chilling sensitivity and storage temperatures, and environmental impacts incurred by harvest date. The negative effects of allowing zinnia ‘Benary Giant Deep Red’ stems to dry up to 4 h after hydrating were negated by recutting stems and removing 2.5 cm of the stem. However, if zinnia stems did not dry out, then recutting had either no effect or a negative impact. Zinnia stems did not rehydrate if allowed to dry for 24 h or more and recutting various amounts from stem ends before placing in vases demonstrated no significant effect on vase life, nor did varying the number of stems per vase. Vase life increased by 2.2 d when stems were stored in a 0.01845 mL L−1 sodium hypochlorite solution versus tap water. Postharvest quality of zinnia was affected by storage temperature such that the longest vase life of 13.0 d occurred when stems were stored for 5 h at 5 °C followed by 2 d storage at 1 °C. As storage temperature increased, zinnia vase life decreased, with the shortest vase life of 6.5 d occurring when stems were stored for 48 h at 20 °C. Vase life continually declined when zinnia stems were harvested every 2 wks from 27 July to 19 Oct. The use of floral preservatives increased vase life late in the harvest season but was not comparable to the extended vase life obtained earlier in the season. Zinnia vase life increased by 2.1 d with the use of a floral preservative (Floralife® Professional) as a 20 h pulse solution in lieu of tap water only. The main findings of this research show that zinnia stems can tolerate a short period of desiccation, while storing stems in a floral preservative and incorporating a brief cold storage period of 1–3 d at 1–5 °C increased vase life. Chilling sensitivity was not observed. Conversely, vase life was observed to be negatively correlated with late season harvesting.

Can Edible Coatings Maintain Sweet Pepper Quality after Prolonged Storage at Sub-Optimal Temperatures?

This work evaluated the efficacies of different coatings: chitosan, gelatin and chitosan-gelatin applied layer-by-layer (LbL); for maintaining the quality of sweet peppers that were stored for 3 weeks at a sub-optimal temperature (1.5 °C) and at an optimal storage temperature (7 °C). After the cold-storage period, fruits were kept under marketing conditions (21 °C) for 3 more days. An edible chitosan coating (2%) effectively alleviated chilling injury and the incidence of decay, and also preserved the nutritional quality of sweet peppers that were kept for 3 weeks at 1.5 °C plus 3 more days at 21 °C. The chitosan coating was more effective than the two other coatings. All three coating treatments significantly reduced external CO2 production, as compared to uncoated control fruit. Storage temperatures did not significantly affect external CO2 production, although CO2 production was slightly higher at 1.5 °C. The chitosan coating exhibited good CO2 gas permeability properties and the peppers coated with that material had lower respiration rates than those in the other two experimental treatments or the control. From a practical point of view, chitosan coating could replace the plastic bags previously found to alleviate chilling injury in peppers that are stored at 1.5 °C as a quarantine treatment.

Changes in the Fungal Community Assembly of Apple Fruit Following Postharvest Application of the Yeast Biocontrol Agent Metschnikowia fructicola

Recently, increasing focus has been placed on exploring fruit microbiomes and their association with their hosts. Investigation of the fruit surface microbiome of apple has revealed variations in the composition and structure depending on management practices, phenological stages, and spatial distribution on the fruit itself. However, the fate of the fruit surface microbiome assembly and dynamics in apple following interventions such as the application of biocontrol agents remains unknown. The objective of the study was to explore the effect of a postharvest application of a yeast biocontrol agent, Metschnikowia fructicola, on the composition of the epiphytic fungal microbiota on apples during cold storage. Our results demonstrated that the applied biocontrol agent, M. fructicola, persisted in high abundance (>28% relative abundance) on the fruit surface throughout the storage period. The biocontrol application significantly decreased the richness and caused a significant shift in the overall composition and structure of the fungal microbiome relative to untreated or water-treated controls. The yeast application reduced the abundance of several apple fungal pathogens, namely, Alternaria, Aspergillus, Comoclatris, Stemphylium, Nigrospora, Penicillium, and Podosphaera, throughout the cold storage period.

Fermented Cranberry Fortified Buckwheat Product—Phenolic Composition, Antioxidant and Microbiological Properties

This study determined the effect of fermentation by Fresco DVS 1010 starter culture with added probiotic strain Lactobacillus rhamnosus GG and potentially probiotic isolate Lactobacillus plantarum HM1, at fermentation times (0, 8 h) and cold storage period (24 h, 4th day, 7th day, 14th day), on microbial parameters, pH changes, total phenolic content, phenolic compounds profile, and antioxidant activity of buckwheat water- and milk-based mashes, flavored with cranberries and unflavored. The tested starter Fresco culture effectively fermented the buckwheat products and the viable cell counts of potentially probiotic bacteria were sufficient to demonstrate the health-promoting properties of final products. Lactic acid bacteria had a positive impact on total phenolic compound content, total flavonoid content, and antioxidant activity of buckwheat mashes, whereby final values (14 days) were higher by about 16.9–130.8%, 13.4–37.7%, and 14.5–145.9%, respectively, in comparison to initial values (0 h). Seven phenolic acids (gallic, protocatechuic, vanillic, syringic, caffeic, p-coumaric, and ferulic) and two flavonoids (rutin and quercetin) in buckwheat mashes were measured during the experimental period. The content of quercetin, gallic, and protocatechuic acids increased and, conversely, p-coumaric acid decreased, in all products. Prepared buckwheat fermented products have the potential to meet the criteria for potentially functional foods.

Edible coatings maintain the phytochemicals in cold-stored ‘Kinnow’ mandarin (Citrus nobilis Lour x C. deliciosa Tenora) fruit

Edible coatings usually maintain or improve the scavenger antioxidants and activities of defense-related enzymes consequently preserve the bioactive compounds. The effects of different coating treatments e.g. carboxymethylcellulose (CMC; 1.0, 1.5 and 2.0 g L-1), chitosan (0.5, 1.0 and 1.5 g L-1), beeswax (5, 10 and 15 g L-1) and control (uncoated fruit) and cold storage period (5-7 ºC, 90-95 % RH for 75 days) on the levels of total phenols, total antioxidant activity, flavonoids, protein, total free amino acids and sugars (total and reducing sugars) in the juice of cold-stored ‘Kinnow’ mandarin fruit were assessed in 2017-18 and 2018-19. The fruit used in the experiment were harvested from the fifteen-year-old healthy trees previously grafted on rough lemon rootstock (Citrus jambhiri L.) and grown in the same block. The fruit coated with different coating treatments were stored at 5-7 ºC and 90-95 % RH for different storage periods (0, 30, 45, 60 and 75 days). The levels of total phenols, flavonoids, total antioxidant activity, total and reducing sugars in the fresh juice of the cold-stored fruit were determined following each cold storage period. Amongst different coating treatments tested, CMC (2.0 g L-1) coating proved to be the best treatment to maintain highest levels of bioactive compounds viz., total phenols, total antioxidant activity, flavonoids and total and reducing sugars as compared to the control during cold storage. In conclusion, coating with CMC (2.0 g L-1) was effective to extend the cold storage life and maintain the highest levels of health-promoting compounds in ‘Kinnow’ mandarin fruit without any symptoms of its toxicity to the fruit

The Effects of Cold Stratification, Cold Storage and Gibberellic acid (GA3) on Seed Germination of Bilberry (Vaccinium myrtillus L.)

Abstract
 Aim of study: The effects of cold stratification, cold storage and gibberellic acid (GA3) on seed germination of bilberry (Vaccinium myrtillus L.) were investigated. 
 Area of study: Ripe berries of V.myrtillus were collected from the Kaz Mountains (İda Mount) National Park-Balıkesir province in Turkey. 
 Material and methods: In the study five levels of cold moist stratification period, cold dry storage period (control, 15, 30, 60, 90 days) at +4 ºC and three dose of GA3 (control, 500, 1000, 1500 mg/L) treatments were applied. Data were tested independently by ANOVA according to three factors with three replications. 50 seeds were used for each treatment for each replication. 
 Main results: Cold stratifications, cold storage and GA3 treatments did not increase the germination percentage of bilberry seeds. Germination was found between 23-40% in all experiments. 
 Highlights: Different pretreatments are advised for increasing germination percentage of V. myrtillus L. seeds

Effect of Opuntia ficus-indica Mucilage Edible Coating on Quality, Nutraceutical, and Sensorial Parameters of Minimally Processed Cactus Pear Fruits

Cactus pear (Opuntia ficus-indica (L.) Mill.) is a non-climacteric fruit with a relatively short postharvest life span, being very sensitive to water loss, darkening and decay. Cactus pear is a spiny fruit, and the presence of glochids limits fruit consumption and diffusion; therefore, minimally processing, as well as peel removing, could be an opportunity to improve its availability, consumption, and diffusion in national and international markets. In this study, cactus pear minimally processed fruits were treated with a mucilage-based coating extracted from Opuntia ficus-indica cladodes and stored at 5 °C for 9 days. The effect of mucilage edible coating on the postharvest life, qualitative attributes, and nutraceutical value of fruit were evaluated by colors, firmness, total soluble solids content, titratable acidity, ascorbic acid, betalains and DPPH (2,2-diphenyl-1-picrylhydrazyl). Results showed that mucilage-based coating improved the quality and preserves the nutraceutical value of minimally processed cactus pear fruits during storage. The edible coating was effective in maintaining fruit fresh weight, total soluble solids content, fruit firmness, ascorbic acid and betalain content, sensorial traits, and visual score. Coated fruits showed a significantly lower microbiological growth than uncoated control fruits during the entire cold storage period.

The Effect of Different Cold Storage Period on Total Lipid Amount of Tenebrio molitor (Coleoptera: Tenebrionidae) Larvae

The ever-increasing world population indicates that it is inevitable to consider insects such as Tenebrio molitor, which are used as live food and even human food in some countries, as an alternative food source. Especially T. molitor larvae are a source of food with high nutritive value for including high lipid and protein. The main material of this study was T. molitor cultures. Flour:wheat flour (250 g: 250 g) in a ratio of 1:1 was used as food. 25 g wheat germ and 5 g dry yeast was put in it. Larvae at stages 13-15th were grouped as control and trial groups and kept for 5, 10, 15 and 20 days at specified temperatures. This study seeks answer to the question “will the insect continue to keep its lipid sources during the periods in which it is kept in the cold, or will it continue to use its energy sources since the physiological adaptations it develops are not enough?” This study evaluates the total lipid amount and percentages of T. molitor larvae stored in refrigerator for different periods. Total lipid amount and percentages of the larvae stored in the cold for 5, 10 and 15 days were found to be higher when compared with the control group. A tendency to decrease was observed in larvae kept for 20 days. As a result, it is recommended for producers not to keep in the refrigerator for more than 15 days. Otherwise, it should be considered that there may be a decrease in important energy and food sources.

Chitosan-enriched salicylic acid coatings preserves antioxidant properties and alleviates internal browning of pear fruit under cold storage and supermarket conditions

Pear being climacteric in nature undergoes alterations in antioxidant properties during storage due to intense metabolic activities. In an attempt to maintain antioxidants level, pears were treated either with chitosan (CH) coatings alone (CH 1.0 and 2.0 %) or were incorporated with 2.0 mM salicylic acid (SA) and stored for a period of 67 d under cold temperature (0 – 1 °C and 90–95 % RH) and 20 d under supermarket conditions (20–22 °C and 80–85 % RH). Evaluation study for different physico-chemical attributes of pears suggested that the SA loaded CH coatings restricted the climacteric peak and delayed the polyphenol oxidase (PPO) enzyme activity. As compared to control, these composite coatings promoted the preservation of total phenolics content (TPC), ascorbic acid (AsA) and retained higher total antioxidant activities (TAA) in fruit till 67 d of cold storage period and 20 d under supermarket conditions. Furthermore, CH 2.0 % + SA 2.0 mM coatings strictly impeded the development of internal browning (IB) symptoms of pears throughout storage period. Combined coatings of CH plus SA contributed higher efficacy in terms of maintaining the functional properties of fruit as compared to individual coatings of CH or SA dip.

Application of intermittent warming to enhance postharvest quality and extend the shelf life of pomegranate fruit (Punica granatum)

Intermittent warming (IW) cycles slow down the physiology of fresh horticultural commodities, thereby extending their storage life. We investigated the effects of IW on physiological disorders, physicochemical, sensory parameters and the emission of volatile organic compounds (VOCs) of pomegranate (Punica granatum; cv. Wonderful) fruit during a 3-month cold storage period. Pomegranate fruit batches were subjected to IW cycles of 3d at 5°C, followed by 1 d at 20°C (IW 3d) and 6 d at 5°C, followed by 1 d at 20°C (IW 6d). During cold storage at 5°C, fruit samples were transferred to shelf-life conditions at 20°C for 4 d before analysis was performed monthly. Continuous fruit mass loss was observed across all treatments during storage but was highest (p < 0.05) for untreated samples at the end of this study. Fruit decay was minimized by 15% and 16% for IW 3d and IW 6d, respectively, compared to 42% for the control. In contrast, a higher incidence of chilling injury was observed in the treated fruits than in control. Therefore, IW 3 d at 5°C is recommended for decay reduction in pomegranate fruit (cv. Wonderful) and shelf-life extension for up to 3 months of storage.

Influence of postharvest UV-C illumination on biochemical properties of green beans

In this study, harvested green beans (Phaseolus vulgaris cv. Bourgondia) were subjected to different doses of UV-C illuminations (0.1, 0.3, 0.5 kJ m − 2; low, medium, and high dose, respectively) and stored under modified atmosphere packages (MAP) at 8°C for 25 days. The extension in storage time resulted increase in weight loss, fluctuations in TSS content, and respiration rate. Medium and high doses resulted higher total phenolic contents comparing to control and low dose treatments. No UV-C damage or deterioration was detected during the entire cold storage period, however medium and high doses caused damages to the surface at the beginning 15 days cold storage plus 3 days shelf life (15 d CS plus 3 d SL) period. All doses also resulted in lower respiration rates and higher total sugar content than control. The effects of illumination on reducing sugar and total chlorophyll contents were non-significant. There were no significant effects on antioxidant activity in cold storage, however during shelf-life the high UV-C dose had highest antioxidant activity compared to control and other doses. Low dose had positive effects on the edible quality and maintained the postharvest quality of green beans for 25 days. Our findings showed that low UV-C dose can be recommended commercially to maintain quality of green beans with no surface damage among the UV-C illumination doses tested.

The impact of cold storage durations on Trichogramma evanescens (Westwood) (Hymenoptera: Trichogrammatidae) during their pupal stage.

This experimental study was done at the Biological Control Laboratory, Sakha Agricultural Research Station, Sakha, Kafrelsheikh, Egypt. We aimed to estimate the impact of different cold (10 °C) storage durations [0 (non-cold-stored parasitized eggs), 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days], on Trichogramma evanescens (Westwood) (Hymenoptera: Trichogrammatidae) during the pupal stage using the eggs of Sitotroga cerealella after exposing to T. evanescens. The emergence percentage of non-cold-stored eggs of S. cerealella was higher than all cold-stored durations. Also, the female’s percentages of T. evanescens in the cold storage durations were lower than the non-cold storage one, and they were influenced by extended cold storage durations. There were non-significant differences in the female’s longevity of T. evanescens obtained from 0, 3, and 6 days cold-stored parasitized eggs of S. cerealella at 10 °C, but it began to decrease from those produced after 9 days of cold-stored eggs. In addition, the emergence percentage in F1 progeny of T. evanescens was greater than 50% until 21 days of cold storage. It could be concluded that cold storage reduced the % emergence, % females, female’s longevity, and emergence percentage in F1 progeny of T. evanescens. For a successful biological control program, the decrease of T. evanescens performance after cold storage durations should be considered in mass production, and the release percentage should be increased by the equivalent of a lack of % emergence. Also, the economic importance of using cold storage periods in commercial mass rearing should be assessed in the biological control program.

Effects of long-term frozen storage on the quality and acceptance of gluten-free cassava pasta

Cold storage conditions during long-term periods can be critical for the quality of gluten-free products. The objective of this work was to elaborate gluten-free pasta using cassava starch and study the influence of different storage conditions on the textural and sensorial properties of gluten-pasta compared to regular pasta. Samples were initially frozen at two different temperatures, -50 °C and -150 °C, and then stored for six months at -25 °C. Physicochemical and rheological analyses were used to characterize the pasta dough. Then microbiological, instrumental texture, and sensorial analysis were used to further characterize the pasta throughout the cold storage period of 6 months. The gluten-free pasta's nutritional composition showed low fat and protein content and high crude fiber, carbohydrates, and energy value content in relation to the gluten-containing pasta. Both kinds of pasta dough presented a pseudoplastic behavior; however, the wheat flour pasta presented lower apparent viscosity. The texture profile of frozen pasta during the evaluation period did not significantly vary when comparing the two freezing temperatures. Although the firmness, chewability, and cohesiveness parameters slightly decreased during the storage, losses of firmness were not detected by the judges at the sensorial analysis. Finally, cassava starch pasta had a high acceptance. According to the purchase intention research, the judges routinely consume gluten-free pasta, showing the high commercialization potential of the obtained product.

Quality and volatile organic compounds emission alterations in ‘August Flame’ peaches due to low dose methyl bromide fumigation

As all perishable fruit, peaches must be stored in cold temperature during transportation for maintenance of fruit quality. Australian peaches exported to China must undergo fumigation quarantine treatments prior to shipment for biosecurity reasons. ‘August Flame’ peaches were fumigated with methyl bromide (MB) at the low dosage of 18 g/m3 for 5.5 h at flesh temperature of 18 °C, as a biosecurity disinfestation treatment, with a subsequent cold storage period at 2 °C and 4 °C for 5 and 9 d to simulate air freight transportation. Fruit quality parameters measured during shelf life (SL) were: firmness, index of delta absorbance (IAD), ethylene production and respiration. Four families of volatile organic compounds (VOCs) from samples of fruit flesh and skin were analysed along SL: aldehydes, alcohols, esters and lactones. Overall trends in the evolution of quality parameters and VOCs emissions were identified. Fumigation, under our experimental conditions, anticipated the climacteric ethylene peak, but did not affect fruit quality enough to be detrimental for consumption and did not cause skin or internal disorders. During SL aldehydes decreased, lactones increased, alcohols were higher in skin than in flesh, but none of these general trends were clearly affected by the fumigation.

Cold treatment: an effective post‐harvest disinfestation treatment for Bactrocera tryoni (Diptera: Tephritidae) in ‘gold3’ kiwifruit

AbstractQueensland fruit fly (Qfly), Bactrocera tryoni (Froggatt), is a major quarantine pest of fresh horticultural commodity along the eastern coastal region of Australia and restricts market access of its host commodity. Consequently, various post‐harvest disinfestation treatments are used to facilitate trade and one such treatment for Qfly is ‘cold disinfestation’. Our study evaluated the effect of cold storage as a post‐harvest disinfestation treatment for Qfly on ‘gold3’ kiwifruit (Actinidia chinensis var. gold3‐sungold), a cultivar grown in New Zealand. Qfly is not present in New Zealand but due to its close proximity to Australia, New Zealand's trading partners have shown concern that Qfly presents a biosecurity risk to their own industry. Our study specifically aimed to demonstrate how this risk would be addressed. Experiment 1 investigated developmental rate of the individual life stages of Qfly in ‘gold3’ kiwifruit under optimal Qfly development conditions of 26 ± 1°C and 65 ± 5% rh, while experiment 2 focused on determination of the most cold tolerant life stage of Qfly in ‘gold3’ kiwifruits. Experiment 3 was a large‐scale confirmatory trial undertaken using the most cold tolerant life stage. The results revealed that Qfly successfully developed in ‘gold3’ kiwifruit and that the most‐cold tolerant Qfly life stage was the 1st instar. Our study further demonstrated that storage of ‘gold3’ kiwifruit at 2.5°C (fruit temperature) for a period of ≥12 days resulted in zero Qfly survival. The large‐scale verification trial treated 61,412 first instar and confirmed that storage of ‘gold3’ kiwifruit at 2.5°C for a 14‐day period resulted in 99.9951% mortality of first instar at the 95% confidence level, hence demonstrating a probit 8.7 level of efficacy. A 14‐day cold storage period was used in this confirmatory trial to ensure additional quarantine security. We recommend that if there was any Qfly infestation on ‘gold3’ kiwifruit, a post‐harvest quarantine treatment of cold storage at 2.5°C (fruit temperature) for a 14‐day period must be used to disinfest Qfly from ‘gold3’ kiwifruit.

The application of a phycocyanin extract obtained from Arthrospira platensis as a blue natural colorant in beverages

Currently, the food additive industry has interest in replacing artificial dyes with natural pigments, trying to maintain consumer interest and increase their awareness towards healthy diets. Phycobiliproteins are light-harvesting and water-soluble proteins extracted from cyanobacteria and red algae that can be employed as natural additives. In the present work, a C-phycocyanin extract from the cyanobacterium Arthrospira platensis was tested as blue colorant in beverages to demonstrate that samples containing the protein extract have a color similar to marketed beverages containing synthetic dyes. Using spectroscopy and colorimetry, the extract was characterized and gave evidence of having good properties and good stability in the pH range between 3.0 and 9.0. The staining factors, representing the amount of blue protein needed to reproduce the color of bluish commercial samples, ranged between 15.6 and 111.7 mg·L−1, being sufficiently low in all samples. Additionally, color stability during a short period of cold storage was studied: it demonstrated that isotonic and tonic beverages remained stable throughout the 11-days analysis period with no significant changes. These results prove that the C-phycocyanin extract has potential applications in food as natural colorant, being an alternative option to synthetic coloring molecules.