End Of Storage Period Research Articles

Designing the pH-sensitive indicator based on starch nanoparticle with bromocresol green for monitoring meat spoilage

ABSTRACT The starch nanoparticle, combined with bromocresol green (BCG), served as a pH-sensitive indicator to monitor meat quality throughout an 8-day refrigerated storage period. The meat samples were sealed in package which the pH-sensitive indicator attached to the interior part of packaging lid. The changes in meat quality were evaluated by total volatile base nitrogen (TVBN), pH, total viable count (TVC), sensory analysis, and color in interval of 0, 3, 5, 7, and 8-days storage at 4°C. Initial TVBN values were recorded at 19.6 mg/100 g, increased to 26.6 mg/100 g by the end of storage period. The pH value was significantly increased after 8 days storage at 4°C. The observed color variation in the indicator from yellow to blue was attributed to the concurrent increases in TVBN, TVC, and pH. The indicator color changes had significant correlation with analyzed chemical quality of stored meat. Therefore, the designed BCG pH-sensitive indicator could be effective in monitoring the meat spoilage during storage.

Effect of gamma ray irradiation and packaging on the storage quality of kodo millet (Paspalum scrobiculatum L.) flour

Kodo millet is one of the small millet species, grown widely in the tropical/subtropical regions. In order to prevent the problem of post-harvest losses, various preservation techniques have been used such as irradiation and suitable packaging material. In the present study, shelf life of kodo millet flour was investigated using gamma rays at 1.5 kilogray (kGy) (irradiation, IR) and different packaging materials including low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET) and metallized polypropylene (MPP) for a period of three months. Every fortnight the samples from these treatments were drawn for biochemical changes (moisture, peroxide value, alcoholic acidity and FFA), insect infestation and microbial growth. By the end of storage period, significant (P < 0.01) increase of moisture, peroxide value, alcoholic acidity and FFA content was noticed in the control samples followed by non-irradiated PP (10.50 %, 3.8 mEq/Kg and 1.25%) and LDPE (9.48 %, 3.4 mEq and 1.20 %) packed flour as compared to irradiated MPP and PET packed samples. Insect infestation started after 15 days of storage in steel boxes which increased in countless numbers by the end of storage period. Similarly, insect population was noticed after 30 and 60 days in non irradiated and irradiated PP and LDPE covers respectively. While, there was no insect infestation in case of irradiated MPP and PET packed flour. Significant increase of bacterial load was observed in the control followed by non irradiated PP (4.2 cfu/g) and LDPE (3.8 cfu/g) covers. Sensory tests indicated that the irradiation has no adverse effect on the taste, appearance, flavor and overall acceptability (OAA) of the flat bread made from flour samples stored in these packaging materials. Thus, the kodo millet flour stored in MPP and PET pouches with irradiation dose of 1.5 kGy found to be suitable for safe storage up to three months under room temperature.

Effect of tomato seed mucilage coating enriched with shallot essential oil on frozen rainbow trout (Oncorhynchus mykiss) fillet quality

The present study aimed to investigate the interaction effects of tomato seed mucilage (TSM) coating and shallot essential oil (SEO) (0%, 1%, and 2%) on the physicochemical, and microbial properties of Rainbow Trout (Oncorhynchus mykiss) during frozen storage (0, 1, 2, 3, and 4 months). The results indicated that the TSM coating treatments, especially, with the increase in SEO concentration effectively reduced the total viable count (TVC) and psychrotrophic bacteria count (PTC). Moreover, it decreasing the rate of changes in thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), and peroxide value (PV). The TVB-N levels were within acceptable limits, except for the Ctrl treatment in the fourth month, where the TVB-N in fish fillet was exceeded 25 mg/100g. The incorporation of SEO to the TSM coating led to a decrease in pH variations, protein solubility, and moisture content of the Rainbow Trout fillets during frozen storage. At the end of the storage period, Hardness in the Ctrl treatment at the end of storage period were respectively 14.95%, 21.91%, and 24.52% lower than those in the TSM-0% SEO, TSM-1% SEO, and TSM-2% SEO treatments. Furthermore, at the end of the frozen storage period, the color changes in all treated fillets were significantly lower compared to the Ctrl treatment (p < 0.05). Overall, utilizing a 2% SEO-containing TSM treatment demonstrated the best performance in delaying undesirable qualitative changes. Hence, there is promising potential in using TSM as agricultural waste in combination with active compounds like SEO to produce an active coating. These coatings, according to their characteristics, can serve as a cost-effective, efficient, and safe option for preserving perishable marine products.

Reduced Fertilization to Improve Sustainable Use of Resources and Preserve Postharvest Quality of Fresh-Cut Wild Rocket (Diplotaxis tenuifolia L.) in Soil-Bound and Soilless Cultivation.

Reducing fertilizer input is a goal for helping greenhouse farming to achieve higher sustainability in the production process while preserving overall crop performance and quality. Wild rocket plants were cultivated in a plastic greenhouse divided into two independent sectors, one for soil-bound (SbS) cultivation and another equipped for soilless (ScS) cultivation systems. In both SbS and ScS, the crop was subjected to treatments consisting of a high- and a low-input fertilization program (HF and LF treatment, respectively). Water use efficiency (WUE) and partial factor productivity (PFP) for nutrients (N, P, K, Ca, and Mg for ScS, and N for SbS) were measured. Rocket leaves, separated for the cultivation system and fertilization program and collected at different cuts during the growing cycle, were cold stored at 10 °C until 16 d. On each sampling day (at harvest and during storage), the sensory parameters, respiration rate, dry matter, color, electrolyte leakage, antioxidant activity, total phenols, total chlorophyll and ammonia content were evaluated. In ScS, the PFP for all nutrients supplied as fertilizers showed a significant increase with the LF treatment, with values higher than 30% recorded for N, K, and Ca. As for the postharvest performance, rocket leaves cultivated in ScS showed better qualitative traits than those cultivated in SbS, as suggested by the lower values of ammonia content and electrolyte leakage recorded at the end of storage period in samples grown in ScS. Moreover, in ScS, the data showed lower membrane damage in LF than HF rocket leaves. Finally, regarding total chlorophyll content, even if no effect of each treatment was recorded in SbS, rocket cultivated in ScS showed a better retention of this parameter by applying LF rather than HF treatment. In addition to this, a PLS model (R2 = 0.7) able to predict the cultivation system, using as a variable non-destructively measured total chlorophyll content, was implemented. Low fertilization input, both in SbS and in ScS, allowed satisfying production levels and more sustainable management of nutrients. LF treatment applied to ScS also had in positive effects on the postharvest quality of fresh-cut rocket leaves.

Standardization and Evaluation of Quality Attributes and Bioactive Components of Ginger (Zingiber officinale Roscoe) and Kokum (Garcinia indica Choisy) Based Herbal Tea

The present investigation entitled “Standardization and evaluation of quality attributes and bioactive components of Ginger (Zingiber officinale Roscoe) and Kokum (Garcinia indica Choisy) based herbal tea” was carried out in the Central Instrumentation Laboratory, College of Horticulture, Rajendranagar, Hyderabad. The experiment was carried out with Completely Randomized Design (CRD) with two experiments, experiment-I consists of 7 treatments and three replications. and experiment -II consists of 8 treatments and 3 replications. Tea bags of 3.5grams will be prepared as per the treatments and Standard cup volume of 100 ml is considered for study. The results revealed that the treatment combination of ginger -kokum mix (first best T7 Dry ginger powder 90 % + Dry Kokum powder 10 %), second best -T3 (Dry ginger powder 50 % + Dry kokum powder 50 %) based on organoleptic evaluation were selected from experiment one and proceeded to experiment two for evaluation of ginger kokum based herbal tea. The results related to physico-chemical parameters and organoleptic evaluation indicated that, among the different herbal teas, the treatment T3 (First best -90 %+ Cardamom -10 %) recorded best with pH (4.54) of 0th day, T2 (Second Best -100 % -Control) recorded highest titratable acidity (4.02 %) of 60th day, T2 (Second Best -100 %) recorded best with Ascorbic acid (1.32 mg/100 g) of 0th day. T4 (First best 90 % +Turmeric -10 %) at 0th day found to be best with total Phenol content (88.95 mg GAE/g). The maximum organoleptic score for overall acceptability (8.47) was in “Like very much range” on nine-point hedonic scale which is recorded in treatment T4: (First best-90 % +Tulasi-10 %) at the end of storage period. it can be concluded that T4-(First best -90 % + Tulasi - 10%) and T8 (Second best 90 % + Turmeric -10%) are best two standardized herbal teas from this research work.

Design of Functional Yogurts with Microencapsulated Biologically Active Compounds

The development of functional foods providing health benefits above the basic nutritional needs is of great interest to the food industry. This research aimed to: design functional yogurts with agave inulin and extracts from propolis, rose petals and Spirulina platensis; observe the physicochemical and microbiological changes during storage at 4°C for 21 days; evaluate the sensory characteristics of the new functional products. Three kinds of calcium alginate microcapsules (agave inulin + ethanolic propolis extract; agave inulin + ethanolic propolis extract + rose petals extract; agave inulin + ethanolic propolis extract + Spirulina extract) were prepared and applied in yogurts before the coagulation. During the storage, pH in all experimental groups gradually decreased (reaching values between 3.94 and 4.02 on the 21st day), which corresponded to the increasing titratable acidity (reaching values from 94.17°T to 108.78°T on the 21st day). The application of microcapsules did not affect the coagulation process and number of lactic acid bacteria in yogurts until the end of storage period. To the best of our knowledge, this is the first study to investigate the application of agave inulin, propolis, rose petals and S. platensis extracts in microencapsulated form in traditional Bulgarian yogurt in order to obtain a dairy product with enhanced functional properties. Keywords: Functional foods, Yogurt, Microencapsulation, Propolis, Rose petals, Spirulina platensis

Effect of Lubricants on Properties of Conventional Tablets of Antihypertensive Drugs from Different Biopharmaceutical Classification System

Background: Hypertension is a long-term medical condition in which blood pressure in the arteries is elevated. Hypertension causes coronary artery disease, stroke, heartfailure; kidney diseases etc.to over come hypertension, antihypertensive drugs are used. Objectives: The aim of present work was to find out effectsof lubricants on properties of conventionaltablets containing antihypertensive drugs from different BCS class. Antihypertensive drugs suchas Metoprolol succinate, and Atenolol were selected which represented BCS class I, and II respectively. Methods: Lubricants are the essential components of all solid dosage forms. Sodium stearyl fumarate, a hydrophilic lubricant was compared with Magnesium stearate,a conventional hydrophobic lubricant. Uncoatedtabletswereprepared either by direct compression or wet granulation technique employing sodium stearyl fumarate or magnesium stearate as a lubricant at 1% or 2%, mixing time of lubricants was varied as 3 and 6mins. Results: Irrespective of class of drug, concentration, mixing time and processing method sodium stearyl fumarate turned out to be effective as tablet lubricant than Magnesium stearate. Both the Lubricants, when used at lower concentration and shorter mixing time resulted in superior tablets properties.Direc tcompression method gave better results than wet granulation technique. Both Sodium stearyl fumarate and Magnesium stearate (1%, 3min) were subjected to storage at400± 20C/ 75% RH for 90 days to check effect of aging and storage. Conclusion: According to at the end of storage period up on investigating for different tablet properties there were no significan tchanges observed.

Evaluation of the physicochemical and microbial properties of lamb meat coated with Shirazi balangu seed mucilage-based edible coating containing cell-free supernatant of Levilactobacillus brevis G145

This study was aimed to design a novel edible coating based on Shirazi balangu seed mucilage (SBM) containing cell-free supernatant (CFS) of Levilactobacillus brevis G145 to improve the quality and shelf-life of lamb meat slices during cold storage. The CFS (1 and 2 %) was added to the SBM, and the obtained edible coating was used to coat the meat slices. The samples were stored at 4 °C for 1, 4, 7, and 10 days. In comparison to the control sample, the meat slices coated with SBM+2 %CFS had manifestly lower total viable count (6.62 vs. 13.10 log CFU/g), psychrotrophic count (3.47 vs. 8.80 log CFU/g), Escherichia coli count (0.80 vs. 1.54 log CFU/g), Staphylococcus aureus count (0.81 vs. 1.57 log CFU/g), fungi count (0.68 vs. 2.38 log CFU/g), pH (5.70 vs. 6.51), and peroxide value (4.89 vs. 10.80 meq O2/kg), and higher moisture content (70 vs. 60 %), hardness (67.80 vs. 57.60 N), and sensory properties by the end of storage period. The results of this study revealed that the SBM+CFS- based edible coating increased the shelf-life of lamb meat efficiently.

Uji Komposisi Biochar Sekam Padi Selama Penyimpanan terhadap Viabilitas Isolat RTCR01 sebagai Carrier Pupuk Hayati di Kabupaten Timor Tengah Utara

Carrier material is one of the significant factors for the success of using biofertilizer since it plays an important role in maintaining microbial viability of which contained in it. This study aimed to find out the composition of carrier materials of rice husk biochar for the viability of isolate RTCR01. This study was conducted at Agriculture Laboratory of Timor University. It started out with isolate RTCR01 recultivation, culture making for nutrient broth media, rice husk biochar making, and injection of 10 ml culture of isolate RTCR01 on various compositions of carrier materials of rice husk biochar. Viability of isolate RTCR01 was observed every week using plate count method on PCA media, while data analysis of the effect of rice husk biochar on the bacterial viability used descriptive analysis. Results of this study suggested that the composition that showed the highest viability of isolate RTCR01 was on the first week of storage namely C3: biochar of 500 gr + tapioca flour of 250 gr + cow dung of 250 gr, meanwhile the viability at the end of storage period on the 8th week included C1: biochar of 500 gr. Observation result suggested that all treatments using the composition of rice husk biochar can maintain bacterial viability during the storage period for 8 weeks.

Genotypic Variation with Respect to Post-harvest Losses of Potato on Storage under Ambient Temperature

The experiment was conducted at All India Coordinated Research Project on Potato, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India during two different years (2016 and 2021) to study on the genotypic variation among 25 potato varieties with respect to post-harvest losses and storage. Approximately 5 kg potatoes of each genotype were kept inside perforated plastic containers under ambient temperature for this study. Rottage of tubers on number and weight basis were recorded at 30, 60, 75 and 90 days. Similarly sprouting of tubers in different genotypes was recorded at 75 and 90 days. It was observed that the percentage of tuber rottage on weight basis at the end of storage period (90 days) varied from 2.5% in Kufri Ashoka to 65.1% in Kufri Sinduri. There was also wide variation among different genotypes for sprouting at 75 and 90 days. Five genotypes did not sprout even at 90 days under storage at ambient temperature. Maximum storage loss of 86.9% was observed in Kufri Sinduri while minimum storage loss was recorded in Kufri Ashoka (8.5%). Highest direct effect on storage loss was exerted by percentage of rottage at 90 days. The direct effect of sprouting at 75 and 90 days on storage loss was very less clearly indicating its minor role. Weight loss of tubers of varying weights (20–40 g, 40–60 g and &gt;60 g) in two varieties were also taken into consideration at 4, 7, 11, 18 and 26 days. The variety Kufri Pukhraj exhibited higher weight loss than Kufri Surya for all grades of tubers. The tubers weighing 20–40 g had the highest weight loss (1.22–2.81) among all the grades. However, the tubers of &gt;60g showed the least weight loss in both the varieties.

Development of spice mixture (Masala) for gluten free pasta and its shelf life study

Spirulina was incorporated to gluten free Quality Protein Maize (QPM) pasta at various levels (2, 4, 6, 8 and 10%) to standardise the level of incorporation. The suitable flour ratio among several combinations tested for gluten free pasta was determined to be QPM flour (Q) 60%, black gram flour (B) 30%, defatted soy flour (S) 8% and guar gum (G) 2% (Q60:B30:S8:G2) for QPM pasta and QPM flour (Q) 60%, black gram flour (B) 30%, Spirulina (Sp) 6%, defatted soy flour (S) 2% and guar gum (G) 2% (Q60:B30:S2:Sp6:G2) for spirulina pasta. Steaming the ingredients for one hour, mixing and kneading for 30 minutes followed by refrigeration (4 °C for 15 minutes) yielded a rupture free pasta. Spice mixture M5 containing salt (1.5 g), turmeric (1.5 g), coriander seeds (1.5 g), red chilli powder (1.2 g), corn flour (0.75 g), citric acid (0.3 g) and fenugreek seeds (0.1 g) at the rate of 10 g per 100 g of pasta was best accepted among different combinations tested (M1, M2, M3, M4 and M5). The sensory scores of gluten free (QPM and Spirulina pasta) and control pasta (100% whole wheat flour) was found to be within the acceptable range (> 7.5 sensory score) in both the packaging materials during six months of storage. The increase in moisture content of pasta irrespective of the type of packaging was noticed. The highest peroxide value was noticed in polyethylene terephthalate (PET) package which indicated that metalized polyester polyethylene (MPP) package had high oxygen barrier property than PET package. At the end of storage period, QPM pasta had slightly higher values for FFA followed by spirulina pasta.

DEVELOPMENT AND OPTIMIZATION OF BLACK MULBERRY RTS DRINK

Present study was conducted during the year 2020 at the Food Technology Section of Postharvest Research Centre, Ayub Agricultural Research Institute, Faisalabad, Pakistan on the value addition of short seasoned indigenous fruit for the development of black mulberry RTS drink. The nutritional quality and effect of storage on the keeping quality of drink was evaluated. Drinks were developed by using different percentage of pulp in final ceipe, filtered, pasteurized and filled in glass bottles. The physicochemical characteristics of the drinks during shelf life were studied. Four drinks with different mulberry fruit juice percentage were prepared and stored them at ambient temperature. The total soluble solids were found to be 13.03, 13.60, 13.86 and 14.20 ⸰ Brix in T1 , T2 , T3 and T4 respectively. During the three months storage periods TSS was reached up to 14.06, 14.13, 14.16 and 14.63 for T1 , T2 , T3 and T4 , respectively. Reducing and total sugars % were increased and observed in the range of (7.20-7.47%), (7.65-7.89%), (7.75- 7.89%), (8.26-9.25%) and (12.52-12.68%), (13.20-13.69%), (13.68-14.98%), (14.52-15.4%) for T1 , T2 , T3 , and T4 , respectively. Non-reducing sugar percent was observed to be reduced from 5.32 to 5.21%, 5.89 to 5.63%, 6.23-6.11% and 6.26 to 6.20% for T1 , T2 , T3 and T4 , respectively during three month storage period. Sensory evaluation showed all the treatments acceptable but highest scores for color, flavour, taste and overall acceptability were perceived in case of T4 with 25% fruit pulp at the end of storage period.

Active electrospun nanofiber packaging maintains the preservation quality and antioxidant activity of blackberry

In this study, an electrospun nanofibrous material, based on polylactic acid (PLA) and polycaprolactone (PCL) and containing an oregano essential oil (OEO)/β-cyclodextrin (β-CD) inclusion complex, was developed for active packaging. The effects of nanocomposite packaging on the preservation quality and antioxidant activity of blackberries were investigated. The OEO@ β-CDs/PLA/PCL nanofiber packaging maintained the appearance of the blackberries and inhibited color deterioration with a* of 0.21 and total color difference of 2.03 on day 10. At the end of storage period, the decay rate was 27.8% and weight loss was 3.56% in OEO@ β-CDs/PLA/PCL, lower than those of other treatments. OEO@ β-CDs/PLA/PCL delayed the softening of the blackberries, which the firmness was 6.78 N on day 10. Moreover, other preservation quality losses were also mitigated by OEO@ β-CDs/PLA/PCL, with total soluble solid of 8.94, soluble protein of 14.03 g/kg and ascorbic acid of 0.195 g/kg on day 10. The nanofibrous film maintained the activity of antioxidant enzymes and inhibited oxidative damage in the microstructure with a low H2O2 content of 0.13 mol/kg. During the postharvest period, the OEO@ β-CDs/PLA/PCL nanofibrous material inhibited postharvest decay and deterioration, loss of nutritional quality and oxidative damage of the blackberries, thereby demonstrating the potential of nanocomposite materials for fruit storage.

Effect of microwave mild heat treatment on postharvest quality of table grapes

Table grapes are characterized by high susceptibility to mold development during post-harvest, mostly due to Botrytis cinerea. Microwave application on ready-to-eat product can represent an alternative to antifungal treatment. With the aim of identifying the maximum energy that can be applied on grape without detrimental effects a Central Composite Design was developed testing the application of 10 combinations of treatment time (seconds) and microwave power (Watt). As a result, energies above 8000 kJ negatively affected the sensorial quality of fresh product, both in the presence and absence of B. cinerea inoculum (106 log CFU g-1). The physico-chemical parameters did not show significant differences, but two time/power combinations improved sensory quality of table grape, being selected for the subsequent packaging trial: 14 s/100 W and 80 s/100 W. Treatments were applied before or after packaging in polypropylene bags. At the end of storage period, 100 W applied for 80 seconds before packaging led to a better external appearance of the product than the other treatments, maintaining an intermediate level of mesophilic bacterial load and no significant differences in terms of nutritional quality. 80 seconds at 100 Watt combined with packaging can represent a valuable starting point for further experiments.

Effect of postharvest spermidine treatments on quality and biochemical properties of nectarine fruits

In this study, the effect of spermidine (SP) treatments at different doses after harvest on the changes in the pomological and biochemical contents of nectarine fruits was determined. The fruits were placed in cold storage (4 ± 0.5 °C and 90 ± 5% RH) for 30 days. Specific organic acids and phenolic compounds from biochemical compounds were analyzed by HPLC device. Weight loss and decay values, which are quality criteria of nectarine fruits, increased during storage compared to the harvest period. In this study, 1.0 mM SP application was found to be more successful in the preservation of visual quality (fruit pulp firmness and weight loss) properties during storage. At the end of the storage period (30th day), weight loss was determined as 3.27% in the control group and 1.84% in the 1.5 mM SP treatment. Fruit flesh firmness value, which is one of the important quality parameters affecting the storage life of fruits, was determined as 30.97 N in the control group and 37.06 N in 1.5 mM SP doze (30th day). Contrary to the acidity values, the total soluble solids content (TSS) and fruit juice pH values increased during storage. In this research, when the organic acid and phenolic compound contents are examined; it was determined that the dominant organic acid and phenolic compound in nectarine fruits were malic acid and chlorogenic acid, respectively. The malic acid ratio was found to be 4.89 g/kg in the control group and 6.66 g/kg in 1.5 mM SP treatment at the end of the 30-day storage period. Chlorogenic acid content was recorded as 6.86 mg/100g in the control group and 8.82 mg/100g in 1.5 mM SP application at the end of the storage period (30th day). In this study, it was determined that a 1.5 mM SP dose after harvest was effective on the biochemical contents of nectarine fruits and protected the fruits more during storage.

Показатели качества Agaricus bisporus после обработки УФ-излучением

Ultraviolet treatment increases the shelf life of plant products. It inhibits the changes in the quality indicators of raw materials that are responsible for storage capacity. The research objective was to establish qualitative indicators for champignons (Agaricus bisporus) after ultraviolet treatment.&#x0D; Fresh champignons were placed in plastic trays and sealed in plastic bags. The samples were treated with ultraviolet radiation in ranges A, B, and C. After that, they were stored in a refrigerator at 4 ± 2°C for 16 days, i.e., until the end of storage period. The quality indicators underwent a paired two-sample test, which defined the equality/inequality of variances in replicates and equality/inequality of means at a given error probability (α).&#x0D; The obtained indicators characterized the degradation of mushroom plant tissue after ultraviolet treatment during storage: texture, moisture content, weight loss, soluble solids, pH, lightness, and color. The authors developed a new approach to determine significant changes in the quality indicators and estimated probability values. For each range, they established the most effective dose at α = 0.05 and 0.1. All the indicators proved significant for range A samples at 327.8–800.0 J/m2 and α = 0.05; all indicators were significant except weight loss in the range from 219.5 to 800.0 J/m2 at α = 0.1. For range B samples, pH, color, and lightness were significant at 104.6–200.0 J/m2 and α = 0.05; all but mass loss and texture were significant at 172.2–200.0 J/m2 and α = 0.1. For range C samples, pH, color, and lightness were significant at 412.4–439.5 J/m2 and 755.9–800.0 J/m2 at α = 0.05; all indicators were significant at 363.3–486.2 J/m2 and 728.2–800.0 J/m2 at α = 0.1.&#x0D; The new analytical method made it possible to determine the ranges of external effect intensity, in which the changes in the indicator were significant or insignificant.

Efficacy of vitamin E with or without probiotic, astaxanthin or rosemary extract on microbiological and chemical characteristics of fresh and frozen fillet of rainbow trout (Oncorhynchus mykiss)

Microbiological properties, proximate composition, total volatile base nitrogen (TVB-N), pH, fatty acid (FA) composition, peroxide value (PV), free fatty acids (FFA), histamine and water holding capacity (WHC) in fresh and frozen-stored (3, 6, and 12 months at −18 °C) fillets of rainbow trout (Oncorhynchus mykiss) (170.46 ± 1.16 g) fed diets containing 50 mg vitamin E (control) alone or with 200 mg vitamin E (VE), 500 mg probiotic (PR), 50 mg astaxanthin (AS) and 500 mg rosemary extract (RE) kg−1 for 4 months were assessed. Decreasing trends in fillet WHC (specially in control and AS groups) were observed in the 12-month storage. Although a low increase in fillet bacterial population occurred during the storage time in all groups, lower bacterial counts were observed in PR group. Fillet histamine, TVN and pH levels were in the accepted ranges in all treatments during the storage. Also, FFA level and proximate composition of fillets didn’t show any significant change during the storage time. The PR diet controlled microbiological activity and variations of pH and PV of fillet samples better than the other experimental diets. It also prepared an appropriate FA composition and retained the desired amounts of both n-3 and n-6 polyunsaturated fatty acids (PUFAs) in fish fillets until the end of storage period, while no significant differences were seen in values of TVN, pH, FFA and histamine among the treatments. However, AS and RE diets tended to be less functional maintaining the fillet quality during the storage time than the other experimental diets. According to the results, a diet containing 500 mg bacilli probiotic with 50 mg vitamin E kg−1 could be highly efficient in maintaining a good quality of trout fillet stored at − 18°C for 12 months.

Effect of oil-born yeasts on the quality of extra-virgin olive oils of Basilicata region

The olive oil microbiota mainly consists of yeasts, which may positively or negatively affect the physicochemical and sensory features of product.In this study, 17 yeast strains belonging to Candida boidinii, Lachancea fermentati, Nakazawaea molendinolei, N. wickerhamii and Schwanniomyces polymorphus species were collected during olive oil production, identified and tested for the ability to ferment sugars, to grow at low temperatures, for the occurrence of different enzymatic activities, for the tolerance and degradation of phenolic compounds, radical scavenging activities, biofilm formation, survival to simulated gastro-intestinal (GIT) tract. Yeasts were also inoculated in extra virgin olive oils (EVOO; from Leccino and Coratina cultivar) to evaluate their survival and their effect on EVOO quality (changes in analytical indices) during 6-months of storage.Most of strains were able to grow at 15°C, while the ability to ferment different sugars was strain-specific. All strains had β-glucosidase activity, while none exhibited lipolytic activity; peroxidase was widespread among the strains, while protease activity was strain-dependent. Esterase and the ability to hydrolyse oleuropein and form hydroxytyrosol was present only in N. wickerhamii strains. All strains were able to survive in olive mill wastewater, used as a model of phenolic compounds-rich matrix. A potential biofilm formation was observed only in N. wickerhamii, while the ability to scavenge radical and to cope with GIT-associated stresses were strain-dependent.High levels of survival were observed for almost strains (except S. polymorphus), in both Leccino and Coratina samples. Yeasts limited the acidity rise in olive oils, but overtime they contributed to increase the parameters related to oxidative phenomena (i.e. peroxides, K232, K270), resulting in a declassification of EVOOs. The total phenolic content (TPC) was correlated to the presence of yeasts and, at the end of storage period (6 months) inoculated samples had significantly lower concentrations compared to the control oils.This study confirms that yeasts are able to survive in olive oils and, therefore, the control of their occurrence during extraction process and storage conditions is needed to obtain high-quality products and to maintain the standards of EVOO classification.

Shear-bond strength of different Self-Etching adhesive systems to dentin with or without laser irradiation before photopolymerization (A comparative Study)

This study aimed at comparing shear-bond strength (SBS) of different self-etching adhesive systems (Clearfil S3 Bond Plus, G-Premio BOND and IBond) to dentin without or with diode-laser irradiation before photo-polymerization and to determine the effect of storage and thermo-cycling on SBS of adhesive systems. Methods: The buccal surface of 84 extracted maxillary premolars was grounded to create flat surface. The specimens were allocated into 3 groups (n = 28) depending upon the adhesive systems, then each group was divided into two sub-group (I, II) (n = 14). After the placement of respective adhesive systems on the flat surface, adhesive system in group I was photo-polymerized immediately, while in group II, the adhesive systems were exposed to diode-laser before photo-polymerization. Composite cylinder (4 mm in diameter and 2 mm height) was built on the flat surface of each specimen. Then group I and II were divided into two sub-groups (n = 7) according to the storage time and thermo-cycling (1 day without thermo-cycling or 72 days with thermo-cycling) then all the specimens were stored in distilled water. The SBS was measured at the end of storage period. ANOVA, Duncan’s Multiple Range Test and independent t-test “P ≤ 0.05” were used for data analysis. Results: G-premio BOND showed the highest mean value of SBS followed by Clearfil S3 Bond plus without significant difference between them, while IBond revealed the least mean value. Laser irradiation had positive effect on the bond-strength of all tested adhesive systems. The results also showed that the storage with thermo-cycling had negative effect on the bond-strength in groups without laser irradiation for all tested adhesive systems, while for groups with laser irradiation, the reduction in the bond-strength of all tested adhesive systems was not significant. Conclusion: Diode-laser application prior to photo-polymerization of self-etch adhesive systems significantly increased the bond-strength to dentin and can increase the durability of composite adhesion.

Improvement of the shelf life of grey mullet (Mugil cephalus) fish steaks using edible coatings containing chitosan, nanochitosan, and clove oil during refrigerated storage

The effects of edible coatings made of chitosan, or chitosan nanoparticles, and their combinations with clove oil on the physical, chemical, microbiological, and sensory properties of grey mullet (Mugil cephalus) steaks during refrigerated storage (4 °C) for 24 days were evaluated. The data indicated that metrics for all of these characteristics were improved significantly (P ≤ 0.05) in coated fish steak samples compared to the control sample. The coated steaks texture values were higher than those of control sample through storage time with nanochitosan coating containing clove oil having best value 2.51 kg/cm2 among tested samples at the end of storage period. However, pH values of coated samples were lower, a good indicator, than corresponding one of the control (6.46) with nanochitosan coatings with or without clove oil showed low mean values (6.11–6.13). Similar trend regarding chemical indices, i.e. total volatile basic-nitrogen, trimethylamine, peroxide, and thiobarbituric acid reactive substances values for samples coated with nanochitosan with or without clove oil giving better lower values than control or other treatments. Also, the coating delayed microbial (aerobic plate count, psychrotrophic bacteria, yeasts and molds, and total coliform bacteria) growth during the refrigeration storage period, and coated samples produced better results compared to the control sample. Sensory evaluations showed that the treatment enhanced the scores of fish steak samples compared to the control. The results showed that a nanochitosan coating with clove oil was the best treatment prolonged the shelf life of mullet steaks and efficiently maintained the quality attributes to an acceptable level during refrigerated storage for 24 days. Thus, these findings can be bases for producer to provide consumers with fresh fish steaks with good shelf life at refrigerated temperature for up to 24 days.Graphical