Days Of Cold Storage Research Articles

Shelf life quality retention and decay inhibition of winter jujube (Zizyphus jujuba Mill. cv. Dalidongzao) using 1-methylcyclopropene

Winter jujube is susceptible to cold stress during cold storage, resulting in quality deterioration. Shelf life of winter jujube after cold storage has not been investigated. This study investigated the effects of 1.0 μL L−1 1-methylcyclopropene (1-MCP) fumigation treatment for 24 h on the quality characteristics of jujube fruits (Zizyphus jujuba Mill. cv. Dalidongzao) during cold storage. The jujubes from the early experimental stage (0 d) were stored at room temperature (20 ± 1 °C) to estimate the shelf life. The remaining jujubes were transferred to cold storage at 0 ± 1 °C and were removed during the middle (40 d) and the later (60 d) stages of the experiment. The decay rate, firmness, color, titratable acidity, total phenolics and flavonoids, antioxidant activity, and antioxidant enzyme activity of winter jujube were measured every 3 days until the end of shelf life. The results indicated that the application of 1-MCP treatment extended the time for jujube to exceed a decay rate of more than 10 % by three days after 40 and 60 days of cold storage. 1-MCP treatment effectively retard the decrease of total phenolic and flavonoid content in jujube, and maintain high free radical scavenging ability and antioxidant enzyme activity throughout shelf life storage.

How Does the Agro-Ecological Conditions Grown Kiwifruit (Actinidia deliciosa) Affect the Fruit Quality Traits and Bioactive Compounds during Shelf Life?

The kiwifruit (Actinidia deliciosa cv. ‘Hayward’), which shows climacteric characteristics, continues to ripen after harvest. In this process, quality losses occur in fruits, and this causes economic losses. The post-harvest storage conditions are essential in preventing these losses. The main purpose of this study was to assess the effect of agro-ecological conditions on quality traits and bioactive compounds of the kiwifruit throughout the shelf life. In this study, kiwifruit grown in 5 different locations (Ordu, Giresun, Rize, Samsun, and Yalova) constituted the plant material of the study. The fruits treated with modified atmosphere packaging (MAP) were stored at 0 ± 0.5 °C and 90 ± 5% relative humidity (RH) for 150 days in cold storage. For shelf life measurements, fruits were kept at 20 ± 1 °C and 65 ± 5% RH for 5 d. Quality analysis was performed at monthly intervals (at harvest, 30th, 60th, 90th, 120th, and 150th d). In this study, the lowest respiration rate at the end of the shelf life was measured in kiwifruit grown in Yalova. Flesh firmness was higher in kiwifruit grown in Rize, Ordu, and Giresun than Samsun. In all periods, Yalova’s L* value in flesh was higher than that of Ordu. The opposite situation was observed for the hue angle. The soluble solids content (SSC) values measured in Samsun and Yalova were higher than in Ordu and Rize. In the last four measurements, higher vitamin C was detected in Yalova than in Ordu, Rize and Giresun. In all periods, the highest total phenolics and antioxidant activity (in DPPH assay) were obtained in kiwifruit grown in Yalova. On the contrary, the highest flavonoids were measured in kiwifruit grown in Ordu. As a result, it was revealed that agro-ecological conditions may affect the quality traits and bioactive compounds of kiwifruit.

Beetroot Stalk Extract as a Functional Colorant for Stirred Yogurt Beverages: Effect on Nutritional Value and Stability during Storage

Betalains are natural red colorants characterized by their stability to anthocyanins, particularly in acidic foods. Beetroot stalks are a good source of betalains, with higher bioactive components than the whole root. Hence, the current study aims to investigate the potential use of beetroot stalk water extract (BSE) as a functional colorant for raspberry-flavored stirred yogurt. For this purpose, the betalains of BSE and their stability at pH 4 and 5 were investigated in addition to the phenolic and flavonoid content. Furthermore, the antioxidant and antimicrobial activities of BSE were characterized. Subsequently, BSE was added to raspberry-flavored stirred yogurt at concentrations of 1 (T1), 2 (T2), and 5% (T3) to study the stability of betalains, the physicochemical properties, the nutritional value, and the viability of lactic acid bacteria during storage (14 days/4 °C). BSE showed a considerable amount of betalains (456.82 mg/L) and phenolics (139.87 mg/g), with a high content of chlorogenic and ferulic acids. The betalains showed greater stability at pH 4 than pH 5 after 14 days of cold storage (275.05 and 247.00 mg/L, respectively). Applying BSE resulted in a functional beverage with high phenolic content (116.55 ± 1.23 mg/g) and flavonoids (71.77 ± 0.57 mg/g) in T3 (5%) compared to the control (95.11 ± 1.12 and 64.72 ± 0.29 mg/g, respectively). The beverages shared high DPPH scavenging activity (IC50 = 71.68 ± 1.30– 69.18 ± 0.48) compared with the control (78.47 ± 3.27 µL/mL). BSE significantly increased the betalain level in yogurt from 44.19 ± 0.05 mg/L to 67.86 ± 0.54 mg/L, resulting in pale red beverages with a redness value of 6.38–9.68 on day 1. By day 14, the redness of the treatments decreased by 6–18% compared with the first day, reaching 5.25 ± 0.03 (T1), 7.87 ± 0.03 (T2), and 8.43 ± 0.05 (T3) due to the degradation of betalains. Generally, BSE is a promising natural colorant when added to stirred yogurt, and it has preferable physical and sensory properties, as it improves the stability of the red color throughout cold storage and increases the nutritional quality. The use of beet stalks as a natural and functional colorant is presented for the first time in the current investigation.

Physicochemical and antioxidant properties of set-type yogurt supplemented by lyophilized water-soluble Melastoma dodecandrum extract-bearded chitosan-coated nutriosomes

In this study, the physicochemical and sensorial properties of set-type yogurt (STY)-enriched with water-soluble Melastoma dodecandrum Lour. fruit extract (MDLE) loaded nano-nutriosomes (MDLE-NU) or chitosan-coated nano-nutriosomes (CH-MDLE-NU) powder were investigated during 21 days of cold storage at 4 ± 2 °C. The results showed that MDLE powder has a high amount of phenolics, flavonoids, anthocyanins (59.42, 38.61, and 2.10 g/100g, respectively), and antioxidant activity ranging from 54.12 to 71.37 g/100g. MDLE successfully encapsulated in NU and CH-NU, where encapsulation efficacy reached 96.92% and particle size ranged from 144.57 to 172.30 nm with an acceptable range of PDI (<0.3). However, the commercial food custom of normal NU is still challenging, therefore, freeze-drying of MDLE-NU and CH-MDLE-NU can make their usage applicable. Our results showed that adding MDLE-NU and CH-MDLE-NU powder to STY significantly (p < 0.05) improved the color, water holding capacity, microstructure, texture, and sensory evaluation, as well as reduced whey syneresis, and losing fat globules of STY. Despite MDLE powder-enriched STY showing higher polyphenol content and antioxidant activity than MDLE-NU or CH-MDLE-NU, nutriosomes systems protect bioactive compounds of MDLE against unfavorable conditions in yogurt during cold storage. In which the reduction of total phenolics, total flavonoids, and total anthocyanins from STY-MDLE at the end of storage (21st day) was 2.7, 4.82, and 17.4%, while was 1.02, 2.6, and 3.03%, in STY–CH–MDLE-NU, respectively. This study indicates that MDLE is a promising ingredient to produce functional foods, besides, nutriosomes systems are a promising nanocarrier to encapsulate and protect the bioactive compounds.

Reformulation of Bologna Sausage by Total Pork Backfat Replacement with an Emulsion Gel Based on Olive, Walnut, and Chia Oils, and Stabilized with Chitosan.

Bologna sausage, also called "la grassa", is a very popular meat product despite its high fat content and lipidic profile raising serious negative health concerns. An emulsion gel containing olive, walnut, and chia oils, stabilized with soy protein isolate, transglutaminase, and chitosan, was used as total pork backfat replacer in Bologna sausage. The nutritional, textural, and technological properties were assessed and sensory analyses were conducted. Color, pH, and lipid oxidation were monitored during 18 days of cold storage (4 °C). A normal fat Bologna sausage was used as a control reference. A decrease in the n-6/n-3 ratio from 16.85 to 1.86 (by 9 times) was achieved in the reformulated product as compared with the control, while the PUFA/SFA ratio increased from 0.57 to 1.61. Color measurements indicated that the lightness and yellowness increased while redness slightly decreased in the reformulated product. The total substitution of pork backfat in Bologna sausage by the emulsion gel developed in the present study was realized without significantly affecting the technological properties, the oxidative stability and the overall acceptance by the consumers.

The effect of summer pruning time and severity on antioxidant capacity and storage quality of Hayward kiwifruit

BACKGROUND Summer pruning of kiwifruit has an important effect on fruit quality and storability. OBJECTIVE: The present study was conducted to investigate the effects of summer pruning time and severity on some quantitative and qualitative characteristics and storability of Hayward kiwifruit. METHODS: The present study was conducted to evaluate summer pruning time (one week after fruit set [1WAFS] and four weeks after fruit set [4WAFS]) and pruning severity (1 - no pruning [control], 2 - shoot pruning after the third or fourth leaf after the last fruit [common pruning], 3 - tip squeezing, and 4 - zero leaf pruning in 20% of fruit-bearing shoots with unlimited growth) on Hayward kiwifruit in 2020 and 2021. RESULTS: The results showed that, at harvest time, the highest average fruit weight and total acid were 124.00 g and 1.74% in the tip squeezing treatment observed in the 4WAFS pruning time in 2021. Zero leaf pruning produced fruits with the highest firmness and antioxidant capacity in 2020 and the highest vitamin C and total phenols in 2021. At the end of 90 days of cold storage, in the tip squeezing treatment, fruit firmness at 4WAFS pruning time was higher than in 1WAFS pruning time in the second year, and the highest antioxidant capacity was in 1WAFS pruning time in the first year. In the second year, the highest vitamin C, firmness, and dry matter were obtained in the zero leaf pruning treatment. In this treatment, the highest total phenols and antioxidant capacity were 133.96 mg GAE/100 g FW and 86.75%, respectively, observed in 4WAFS pruning time in the second year. CONCLUSIONS: Overall, tip squeezing and zero leaf pruning at the time of 4WAFS improved the quantitative and qualitative characteristics at the harvest and cold storage.

Development of hydroxypropyl methylcellulose films with corn silk polysaccharides and its application as biomaterial in enhancing the shelf life of mozzarella cheese

AbstractHydroxypropyl methylcellulose (HPM) is a viscous modified natural polymer that is utilised as thickener, emulsifier and reducer of serum cholesterol. Novel films composed from HPM and corn silk polysaccharides (CSP) were prepared (HPM‐corn silk [CS]). The impact of using different percentages of CSP on the characteristics of HPM‐CS was studied. Results showed that replacing 37.5% of HPM with CSP led to a significant improvement in mechanical properties, with an increase of 58.71% for tensile strength and 54.29% for elongation at break. In addition, the produced films showed improved opacity, antioxidant activities and a smooth, continuous surface without any grooves, as well as being biodegradable. However, the thermal stability was reduced, and the crystallinity shapes were disrupted at higher concentrations due to the inclusion of CSP in the HPM‐CS films. The best HPM concentration (1 g/100 mL) with optimum CSP concentration of (0.6 g/100 mL) was used as food packaging material for low‐moisture mozzarella cheese. The packaging material kept the stability of total microbial count in hygienic scale up to 40 days of cold storage, moisture loss and pH values up to 30 days. Additionally, the results of hedonic sensory evaluation were satisfied compared with fresh cheese until 30 days of storage.

Production of a Probiotic Soy-Soursop Yogurt Containing Lactobacillus rhamnosus yoba 2012

There is an increasing demand for functional food products developed from local resources. In this work, Lactobacillus (Lb.) rhamnosus yoba 2012 and Streptococcus thermophilus were used to produce a soy-soursop probiotic yogurt. Soy milk was supplemented with soursop pulp in amounts of 0%, 5%, 10%, and 15%. The mixtures were pasteurized at 85 °C for 15 s, cooled, inoculated with a starter and incubated at 45 °C for 24 h. Samples were taken at 0, 2, 4, 6 and 24 hours for analysis of pH, acidity, and Lb. rhamnosus yoba 2012 counts. Consumer acceptability and willingness to purchase were determined after 24 h of fermentation. The most acceptable sample was analyzed for nutritional composition. Lb. rhamnosus grew in the soy-soursop yogurt up to 8.1-9.3 log cfu/mL. The highest cell growth was observed in yogurt containing 5% soursop whereas the lowest was observed in yogurt containing 15% soursop. Yogurt pH reduced to 3.9-4.4, with 15% soursop having the lowest pH (p&lt;0.05). Titratable acidity increased to 0.6%-0.9% lactic acid. All the yogurts were accepted although those containing 15% soursop had the lowest scores (5 = neither like nor dislike). There were no yeasts, molds or coliforms detected during the 21 days of cold storage (4 ℃) of all the yogurt. Therefore, adding soursop to soymilk produces a satisfactory probiotic soy-soursop yogurt.

Reduced Sodium in White Brined Cheese Production: Artificial Neural Network Modeling for the Prediction of Specific Properties of Brine and Cheese during Storage

Background: White brined cheese is one of the most frequently consumed cheeses that is accepted among a large group of consumers, which is largely related to its unique sensory properties, which are characterized by specific technological processes including ripening in the brine. Thus, white brined cheese contains a high amount of NaCl, and frequent consumption might lead to excessive sodium intake, which nowadays, presents a global problem. Consequently, food industries have developed reduced sodium products by substitutional salts. Furthermore, various studies have indicated that increased sodium intake via the diet can be associated with cardiovascular diseases, a risk of digestive system cancer, obesity, and other conditions. Calcium salts (citrate and lactate) are safe for human health and can be added to various foods according to the quantum satis rule. The present study aimed to partially replace NaCl with Ca-citrate and Ca-lactate in proportions of 25% and 50%. Additionally, the study presents the possibility of applying Artificial Neural Network (ANN) models for the prediction of some brine and cheese properties. Methods: White brined cheese with substitutional salts in brine (25% and 50% Ca-citrate and 25% and 50% Ca-lactate) were produced and compared to the control cheese ripened in conventionally applied NaCl brine. The acidity, total dissolved solids, salt amount, conductivity, color, and textural and sensory properties were determined over the 28 days of cold storage. Results: The substitution of NaCl with Ca-citrate and Ca-lactate is promising for sodium reduction in white brined cheese, whereby the physical and chemical properties remain acceptable. The best sensory score gain occurred with a substitution of 25% NaCl with Ca-citrate. Furthermore, ANN models can be employed to predict brine and cheese properties during storage.

Physicochemical Quality Retention during Cold Storage of Prepackaged Barramundi Meat Processed with a New Microwave-Assisted Induction Heating Technology.

Microwave-assisted induction heating (MAIH) is a composite microwave and induction heating to supply rapid and uniform heating of food. A recent study showed that the optimum MAIH heating condition for barramundi meat was 90 °C/110 s or 70 °C/130 s. This study examines whether the microwave-assisted induction heating (MAIH) technology (at 70 °C for 130 s or 90 °C for 110 s) can more effectively slow down the quality loss of barramundi meat during cold storage than the traditional boiling method (at 90 °C for 150 s). The results show that no microbial growth was observed in the three groups of heated barramundi meat samples during the 60 days of cold storage. However, the MAIH technology slowed down the increase in the total volatile basic nitrogen (TVBN) content more significantly than the boiling method. As the cold storage time increased, though, the L* (lightness), a* (redness), and W (whiteness) values decreased, while the b* (yellowness) and color difference (ΔE) values increased in the three treatment groups. However, the MAIH technology slowed down the decrease in the L*, a*, and W values more significantly, and produced a ΔE value smaller than the boiling method. Moreover, the MAIH technology ensured higher hardness and chewiness of the barramundi meat than the boiling method. Overall, the MAIH technology slowed down the quality loss of the barramundi meat and maintained better color and texture during cold storage.

Potential effect of naturally colored antioxidants from Moringa oleifera, propolis, and grape pomace - Evaluation of color and shelf life of chicken paté

Natural additives are a core topic of food science due to their food safety aspects, and among the natural additives, colorants and antioxidants stand out. The aim of this study was to verify the potential effect of naturally colored antioxidants extracted from Moringa oleifera leaves, propolis and grape pomace on the shelf life of chicken paté. The parameters of TBARS, total volatile basic nitrogen (TVB-N), pH and color were monitored in the paté during 35 days of cold storage at a temperature of 4 ± 1 °C. Moringa extracts, which produced the highest yields, provided a more colorful food product. Grape pomace showed the greatest antioxidant potential and was more efficient in inhibiting lipid oxidation. TVB-N levels remained within the limit considered safe for food in all applications. The total color difference was greater in the first weeks in all treatments, emphasizing that the red grape pomace showed greater color stability.

Impact of Cold Storage Temperature and Shelf Life on Ripening Physiology, Quality Attributes, and Nutritional Value in Apricots-Implication of Cultivar.

This work aimed to investigate the storability potential of Orange Red and Orange Rubis apricots harvested at commercial maturity stage during cold storage (CS) at 1 or 5 °C for up to 28 days, followed by shelf life (SL) at 20 °C for 2 days. The variables evaluated included total soluble solids, titratable acidity, pH only at harvest, weight loss (WL), ethylene production rates, peel color, firmness, chilling injury incidence (CI), concentrations of total phenolics, flavonoids, carotenoids, total antioxidant capacity, b-carotene, b-cryptoxantine, and lutein. The main results showed that storage at 5 °C resulted in higher WL and CI symptoms than at 1 °C during both CS and SL, increased ethylene production during CS, whereas there was limited or no effect of CS temperatures on changes in firmness, color, and all antioxidants during CS. Firmness decreased abruptly soon after harvest in Orange Rubis, but progressively in the remaining samples of both cultivars during CS and SL. SL advanced fruit deterioration according to WL, CI, and softening. During SL, ethylene production increased in all samples. Orange Red exhibited higher ethylene rates during SL and antioxidant concentrations throughout CS and SL, by comparison. Conclusively, storage temperature at 1 °C retained WL, CI, and ethylene production, and both cultivars were marketable up to 21 days CS without SL or up to 14 days CS followed by SL, although Orange Rubis exhibited CI after 14 days, while Orange Red exhibited CI after 21 days of CS.

Use of spermidine to preserve organic acids, polyphenols, and quality of cold stored plum fruits

One of the primary goals of fruit production and storage is to ensure pre-and post-harvest food quality. Polyamines have recently been used to improve food quality after harvest. We used spermidine concentrations of 0.5, 1, and 1.5 mM in plum fruits for 20 and 40 days of cold storage. Each dose provided significantly higher preservation of sensory properties, organic acids, and phenolic compounds than the control, with a gradual improvement by doses. Malic acid was the predominant organic acid and was gradually preserved by spermidine doses, including 25% more malic acid for the 1.5 mM spermidine treatment. Similarly, chlorogenic acid, the most abundant phenolic compound studied, was also 25% higher when the spermidine dose rose to 1.5 mM. The 1.5 mM spermidine notably inhibited weight loss and respiration rate. Organic acids and phenolic compounds were particularly protected by the 1 and 1.5 mM doses, and multivariate approaches suggested that spermidine has a comprehensive stability effect on secondary metabolites. This study proposes spermidine as a comprehensive metabolic preserver that protects polyphenols and organic acids, thus preserving the taste and healthiness of cold-stored plum fruits.

Effect of vacuum and modified atmosphere packaging on moisture state, quality, and microbial communities of grouper (Epinephelus coioides) fillets during cold storage

The study aimed to assess the impact of different packaging methods on the moisture state, quality, and microbial composition of grouper fillets. The grouper fillets were packaged under the following four conditions: vacuum packaging (VP), 70% CO2/30% N2 (MAP1); 60% CO2/30% N2/10% O2 (MAP2); 40% CO2/30% N2/30% O2 (MAP3). Physicochemical and microbiological parameters were evaluated during 21 days of cold storage. The result demonstrated that MAP was effective in inhibiting microbial growth and accumulation of total volatile basic nitrogen (TVB-N), while also maintaining the water-holding capacity (WHC) of grouper fillets. Additionally, MAP1 effectively inhibited lipid and protein oxidation and protected the secondary structure of myofibrils compared to MAP2 and MAP3, with MAP1 samples having the lowest thiobarbituric acid reactive substances (TBARS) value (0.009–0.04 MDA/kg) and carbonyl content (0.20–0.26 μmol/g) and the highest sulfhydryl content (0.25–0.49 μmol/g) during cold storage. The results of high-throughput sequencing revealed that the presence of oxygen in the packaging system significantly influenced bacterial succession. Over time, Carnobacterium gradually became the dominant genera of fillets stored in MAP, and the presence of oxygen in MAP2 and MAP3 accelerated this transition by 9 days, compared to MAP1. In contrast, Enterobacteriaceae and Carnobacterium were the main dominant genera in VP. Remarkably, Enterobacteriaceae were virtually absent in MAP2 and MAP3 during storage, suggesting that the presence of oxygen exerted a significant inhibitory effect on Enterobacteriaceae. This study provides valuable insights into the application of MAP in the preservation of grouper fillets.

Extraction of protein from apricot kernel oil press cake (AKOPC) through innovative techniques and the formulation ofsupplemented yogurt.

The apricot kernel oil press cake (AKOPC) is a high protein natural by-product of oil mechanical expression with potential uses in cosmetics, medicines, and food. The purpose of this research was to improve the protein extraction process from apricot kernel oil press cake by using enzymatic extraction (EEP), aqueous extraction (AEP), and ultrasound extraction (UEP) process. Protein extraction by AEP was facilitated by a low solid-liquid ratio (SLR) (1:15.97) and prolonged reaction durations (3.30 h), resulting in extraction yields of 68%. When compared to the AEP by similar reaction time, increased enzyme utilization (0.90%) in the EEP resulted in greater protein extraction yields (70%) in a shorter reaction time. In addition to AEP and EEP, ultrasound extraction was also used to improve protein extractability. Temperature (50°C), power density (225 W/L), and extraction duration (20 min) were shown to be the best extraction points. Protein yield was found to be 56.47% at ideal UEP conditions. The experimental values for these reactions were found to be equivalent to the predicted values formed by the mathematical models. When supplementary skimmed milk powder (SMP) was substituted with apricot kernel protein (AKP) in the yogurt manufacturing process, the total solids, average titratable acidity, total protein, and fat contents of the yogurt were increased. In contrast, pH and syneresis values decreased as AKP increased in the resulting yogurt, whether fresh or after 7 days of cold storage. Substitution of additional SMP with AKP in yogurt production might be recommended up to 35%.

The Preharvest Application of Essential Oils (Carvacrol, Eugenol, and Thymol) Reduces Fungal Decay in Lemons

Lemon postharvest losses are mainly due to the presence of fungal diseases. Current postharvest decay strategies rely on synthetic chemical fungicides; however, consumers are demanding that fruit is free of any chemical residue. The use of new natural alternatives, including essential oils, is emerging due to their potential antimicrobial activity. Therefore, the aim of this work is the elucidation of the effect of carvacrol, eugenol, and thymol, individually and in combination, applied in preharvest. Three different concentrations (100, 500, and 1000 µL/mL) of carvacrol, eugenol, and thymol were individually applied and in combination in ‘Fino’ and ‘Verna’ lemon cultivars. The fungal incidence (mainly Penicillium digitatum and P. italicum) was evaluated weekly for 35 days. Moreover, the main different quality parameters (weight loss, firmness, colour, total soluble solids, titratable acidity, and total phenolic content) of lemons were evaluated at harvest and after 35 days of cold storage. The results showed that carvacrol at the lowest concentration (100 µL/L) provided the lowest fungal incidence with a non-negative effect on the lemon quality parameters during storage, while the highest concentrations and the combination of essential oils resulted in the opposite effect. Therefore, carvacrol applied at 100 µL/L in preharvest could be an eco-friendly alternative to the current fungicides to control lemon decay, while maintaining their optimal quality.

A comparison of culture and cooling for the short term preservation of in vivo derived dromedary camel embryos of varying morphological quality

Despite recent advancements in the cryopreservation of dromedary camel embryos, widespread application of the technique is still limited by the need for specialised vitrification equipment and supplies. Temporary, liquid-phase embryo storage methods provide a useful tool for short-term preservation of camel embryos.In the current study, we compared the use of in vitro embryo culture with cold liquid storage in order to maintain both high- (Grade 1- Excellent and 2-Good) and low- (Grade 3- Moderate and 4-Poor) morphological grade Day-7 dromedary camel embryos in vitro for up to 3 days. Embryos were either cooled and placed in Hams-F10 medium supplemented with HEPES and 10% FBS and then kept at 4 °C; or placed in Hams-F10 supplemented with sodium bicarbonate and 10% FBS and then cultured in a humidified atmosphere of 6% CO2 at 37 °C before being assessed for viability at 24 h. In high-morphological grade embryos, both cold storage and culture supported 100% viability (maintenance of normal morphology) over this period (Cooled n = 22, Cultured n = 20). In low-morphological grade embryos, culture supported higher viability (16/18, 88.9%) than did cooling (4/18, 22.2%). We then evaluated the effect of up to 3 days of cold storage or culture on embryo morphological grade, diameter, and developmental competence following embryo transfer. High-grade embryos were divided between culture and cold storage; low-grade embryos were evaluated only after culture. Over 3 days of culture, both high- and low-grade embryos tended to either maintain or improve upon their initial morphological score (P < 0.05) and increased in diameter (P < 0.001). Embryos subjected to cooling tended to have reduced morphological scores by 48 h of storage and decreased in diameter by 72 h (P < 0.05). No significant influence of storage method (cooling vs. culture), duration (24–72 h), or embryo grade (high vs low) was observed on pregnancy establishment at Day-60 (22.2%–57.2% pregnancy rates for all treatments). Overall, rates of pregnancy establishment were similar for transferred cultured (n = 45) and cooled (n = 45) embryos (pregnancy rates at Day 18, 48% vs 51.1%; at Day 60, 37.7% vs 37.7%). Rates of embryonic loss also were similar (22.7% vs 26%).In conclusion, whilst similar rates of pregnancy and pregnancy loss were observed following the transfer of both cooled and cultured embryos held in vitro for up to 3 days, amongst the two methods, only embryo culture appears to provide a means of effectively preserving Day- 7 dromedary camel embryos with reduced morphological values in vitro. Considering these embryos appear to show poor tolerance to the cooling procedure and are unlikely candidates for vitrification, embryo culture may provide an effective method for deriving pregnancies from low-morphological grade embryos when immediate transfer is not possible on the day of flushing.

Development of a Novel Beverage with Cactus Juice (Opuntia Ficus Indica) and date Palm sap (Phoenix Dactylifera L)

This study aimed to evaluate the possibility to produce a beverage combining Opuntia ficus Indica juice (OFIJ) and date palm sap (Phoenix dactylifera L.) (DPS). Beverages (B1, B2, B3) were formulated by mixing the juice and date palm sap at different ratios (40:60%, 30:70%, 20:80%) whereas OFIJ and DPS were considered as the controls. Sensory evaluation using 5-point hedonic scale was performed and showed that the control DPS was the most appreciated in term of aftertaste and overall acceptability. Among the formulated beverages B3 is more appreciated than B2, followed by B1. Physico-chemical analysis showed that the sedimentation and serum separation increase considerably after 28 days of cold storage traducing the instability of beverages. Microbial analysis carried out during 42 days of cold storage revealed the absence of total coliforms, Staphylococcus and Escherichia coli for all drinks and that after 28 days of storage the beverages cannot be consumed.

Microbial inhibition and shelf-life extension of longan (Dimocarpus longan) juice by UV radiation

This study aimed to investigate the effects of UV radiation at different doses (0–149.8 J/cm2) and pasteurization process (72 ± 1 °C, 1 min) on the quality preservation of longan juice. Longan juice was inoculated with Escherichia coli and subjected to UV and pasteurization process. UV-149.8 J/cm2, and pasteurized longan juice samples had higher log reduction values of total microbial (2.80 and 3.63), yeast/mold (4.14 and 4.56), and E. coli (2.76 and 4.13) log CFU/mL, respectively, compared to untreated control and other UV treated samples. The first order kinetic model potentially inhibited total microbial count, yeast/molds and E. coli in UV-149.8 J/cm2 sample. pH, total solids, total acidity, and turbidity showed no difference in UV and pasteurized samples. However, color values were affected in pasteurized sample than the UV treatments. Total phenolic content (TPC), total flavonoid content (TFC) and antioxidant (DPPH and FRAP) values were highest in untreated control, followed by the UV-74.88 J/cm2 than that of UV-149.8 J/cm2 and pasteurized samples. Based on the highest bioactivity, UV-74.88 J/cm2 and pasteurized samples were compared for quality changes during 15 days of storage at 4 °C. The selected UV-74.88 J/cm2 sample had higher TPC, TFC, DPPH, and FRAP values than the pasteurized sample up to 12 days of cold storage. Additionally, total plate count and yeast/mold were lowest in UV-74.88 J/cm2 sample in comparison with untreated control. Color values were stable in UV-74.88 J/cm2 sample, compared to pasteurized sample. Pasteurized longan juice showed no growth of yeast/mold during the entire storage period. Therefore, shelf life of UV-74.88 J/cm2 sample was prolonged to 12 days compared to the control sample that became unacceptable after 6 days during storage at 4 °C. UV treatment of longan juice could be considered a promising non-thermal additive free technology for reducing microbial load, improving quality characteristics, and extending shelf life.

Optimal Preharvest Melatonin Applications to Enhance Endogenous Melatonin Content, Harvest and Postharvest Quality of Japanese Plum

Plum is one of the most produced stone fruits worldwide. Melatonin is an environmentally eco-friendly substance that, in low concentrations, activates defence systems against biotic and abiotic stresses. This substance is considered a tool that could increase fruit quality. This study aimed to evaluate the impact of different preharvest foliar applications with different melatonin concentrations (0.1, 0.3, 0.5 mmol L−1) to enhance melatonin content and shelf life of ‘Primetime’ plum. To this purpose, two and three applications were carried out at different critical stages of fruit growth. Different quality characteristics such as size, colour, titratable acidity, total soluble solids, ripening index, respiration rate, ethylene production rate, anthocyanins and total antioxidant activity, as well as endogenous melatonin content, were tested at harvest and after 40 days of cold storage. Results showed that ‘Primetime’ plums that received 3 applications of 0.5 mmol L−1 enhanced endogenous melatonin content at harvest and showed less softening, delayed darkening, higher anthocyanin concentration and total antioxidant activity after 40 days of storage. Therefore, the concentration of 0.5 mmol L−1 melatonin in 3 applications was effective in improving the quality of ‘Primetime’ plums.