Differential Efficacy of Storage Temperature and Postharvest Treatment on Shelf Life and Quality of Avocado Fruit (Persea americana Mill.).

Avocado fruit is a rich source of phytonutrients such as vitamins, minerals, carotenoids, carbohydrates, polyphenols and unsaturated fatty acids. However, due to its climacteric nature, fruits are highly susceptible to storage temperature, resulting in poor shelf life and reduced quality. In the present study avocado fruits (Accession CHES-HA-I/I) were stored at different low temperatures (5, 9 and 12 °C with 90-95% relative humidity, RH) to identify optimum low temperature for cold storage. In a further experiment, avocado fruits were treated with 1-methylcyclopropene (1-MCP, 500 ppb) and chitosan (0.5%) to extend the shelf life with better fruit quality. The results showed that storage temperatures had significant effect on physiological, biochemical and antioxidant activities of fruits. Lower physiological loss in weight (PLW), reduced respiration and ethylene production, and higher carbohydrates, protein and fat content were recorded in fruits stored at 9 °C as compared to 12 °C. Similarly, maximum antioxidant properties in terms of free radical scavenging activity (FRSA) and ferric reducing ability of plasma (FRAP) was found in avocado fruits stored at 9 °C. It was also noticed that chilling injury was developed in fruits stored under 5 °C. In addition, exogenous application of 1-MCP significantly reduced respiration and ethylene production rate at 9 °C and extended the shelf life up to 42 days with better fruit quality and more antioxidant activities. However, chitosan treated and control fruits had shelf life up to 28 and 21 days respectively, with minimum nutritional content. From this study it is concluded that a storage temperature of 9 °C and 1-MCP treatment significantly enhanced the shelf life of avocado fruits with better fruit quality as compared to other storage temperatures (5 and 12 °C) and postharvest treatment (chitosan).

Retention of freshness and isothiocyanates in fresh-cut radish (Raphanus sativus var. Longipinnatus) through glucose dip treatment.

Experiments were carried out with the objective of enhancing shelf life and maintain quality of fresh-cut radish slices during storage at 8 °C. Dip treatment of radish slices in 20 g/L glucose solution for five minutes retained the quality attributes viz., surface colour, sensory properties and antioxidant capacity of the slices till six days of storage. Isothiocyanates were also retained better due to glucose dip. Biplot generated through principal component analysis of head space volatiles from fresh and stored radish slices showed that fresh and glucose treated slices grouped together with 4-methyl thio-3-butenyl isothiocyanate. Accumulation of sulphurous volatiles such as methyl disulphide, dimethyl trisulphide, 2-pentanethiol was observed in control (undipped) radish slices, indicating their probable role as spoilage indicator volatiles. Thus, glucose pre-treatment can be considered as a practical method for quality retention of fresh-cut radish. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05276-1.

CFB box wrapping: a new shrink wrapping technology for extension of storage life of colour capsicum (cv. Bachata).

Capsicums lose water very rapidly after harvest and the moisture loss causes severe shriveling making them unmarketable within 2-3 days. The moisture loss occurs even under low temperature conditions, though at lesser rates. Bell peppers packed in corrugated fiber board boxes (CFB) tend to lose moisture continuously as these boxes are permeable to both water vapour and respiratory gases even if they are non-ventilated. To reduce the moisture loss and maintain freshness, yellow colour capsicum (cv. Bachata) were packed in CFB boxes and over wrapped with different semi-permeable films using shrink wrapping technology. This box shrink wrapping significantly lowered the weight loss and maintained firmness of capsicum at ambient (25.7-33.2 °C and 25-63% RH) and low temperature (8 °C ± 0.5 and 80 ± 5% RH) conditions. Yellow colour capsicums packed in this way could be stored for 11 days at ambient temperature with a weight loss of < 6% as compared to about 20% weight loss in non-wrapped fruits. The storage life could be extended to 5 weeks by storing these shrink wrapped boxes at 8 °C without any shriveling and with a weight loss of < 5%. In addition to maintaining high humidity, the lower O2 and higher CO2 levels maintained surrounding the produce in the wrapped boxes helped to avoid shriveling and to retain the quality in terms of surface colour, firmness and other quality traits. The absorption of excessive relative humidity by CFB itself in the over wrapped boxes helped in avoiding condensation of water droplets. This in turn avoided the development of fungal growth and thus the risk of fruit decay.

Individual shrink wrapping extends the storage life and maintains the quality of pomegranates (cvs. 'Mridula' and 'Bhagwa') at ambient and low temperature.

The present investigation was carried out to study the response of two commercial pomegranate cultivars to individual shrink wrapping in extending the storage life and quality maintenance. Pomegranate fruits ('Mridula' and 'Bhagwa') were individually shrink wrapped using three semi-permeable films (Cryovac® BDF-2001, D-955 and normal LDPE) and stored at ambient (25-32 °C and 49-67% RH) and low temperature (8 °C and 75-80% RH). Shrink wrapping greatly reduced weight loss in both cultivars irrespective of the film used and storage temperature. Weight loss in shrink wrapped (D-955 film) 'Mridula' and 'Bhagwa' after 1 month storage at ambient temperature was respectively 1.40 and 1.05%, when compared to 22.92 and 22.53% in non-wrapped fruits. After 3 months at 8 °C, shrink wrapped 'Mridula' and 'Bhagwa' fruits lost only 0.43 and 0.68% weight respectively, compared to 17.23 and 21.67% in non-wrapped ones. Shrink wrapping significantly reduced the respiration rate at ambient temperature and the response varied with variety and film used. Shrink wrapped fruits of both cultivars retained the original peel colour (Hunter h∘ and C* values) to a maximum extent during 3 months storage at 8 °C and shelf-life period at ambient temperature. Irrespective of variety and film, shrink wrapping maintained the peel thickness and peel moisture content, significantly much higher than non-wrapped fruits at both temperatures. Compared to 'Mridula' cultivar, 'Bhagwa' responded well to shrink wrapping during prolonged storage at both temperatures with better maintenance of quality in terms of appearance, colour, juice content, TSS, acidity, sugars and sensory attributes. At ambient temperature, shrink wrapping with D-955 or LDPE film extended the storage life of 'Mridula' and 'Bhagwa' for 3 weeks and 1 month respectively, whereas at 8 °C both could be stored for 3 months with 3 days of shelf life.

Effect of modified atmosphere packaging on the extension of storage life and quality maintenance of pomegranate (cv. 'Bhagwa') at ambient and low temperatures.

Pomegranates (cv. 'Bhagwa') packed in four semi-permeable films (Cryovac® BDF-2001, D-955, RD-106 and normal LDPE) were stored at ambient temperature (25-30 °C, 60-70% RH) and low temperature (8 °C, 80-85% RH) to study the effect of modified atmosphere (MA) packaging on storage life extension and quality maintenance. O2 and CO2 levels generated inside MA packs differed significantly with the film type wherein extremely high CO2 (> 70%) and low O2 (1% or less) were observed in BDF film during 3 weeks at ambient temperature and 3 months at 8 °C. Moderate O2 (3-8%) and CO2 (7-11%) were maintained in D-955 film, whereas very high O2 (18-20%) and low CO2 (2-4%) were maintained in RD-906 film. Significantly low weight loss of 0.73 and 0.52% was observed in MA packed (D-955) fruits after 3 weeks at ambient and 3 months at 8 °C respectively compared to 19.0 and 17.8% in non-packed fruits. Fruits packed in D-955 film also retained original peel colour (L*, h° and C*), whereas colour was adversely affected in fruits packed in low permeable BDF film. MA packaging maintained peel thickness and peel moisture, significantly higher than non-packed fruits at both temperatures. TSS, acidity, sugars, antioxidants and sensory qualities were better in D-955 and LDPE packed fruits at both ambient and 8 °C storage, whereas quality was adversely affected in BDF film packed fruits. MA packed (D-955 and LDPE) fruits had less spoilage up to 3 weeks at ambient (5.5 and 8.3%) and 3 months at 8 °C (2.8 and 9.7%). Quality got deteriorated by 4 weeks at ambient temperature and 4 months at 8 °C with enhanced spoilage. Pomegranate fruits cv. 'Bhagwa' can thus be stored safely for 3 weeks at ambient and 3 months at 8 °C storage by MA packaging in D-955 or LDPE film with least weight loss and maintenance of nutritional quality.

Salinity-driven decadal changes in phytoplankton community in the NW Arabian Gulf of Kuwait.

Evaluation of hydrological data obtained between 2000 and 2013 from a time series station in Kuwait Bay (station K6) and an offshore southern location (station 18) off Kuwait showed drastic increase in salinity by 6 units. We tested the hypothesis that increased salinity impacted phytoplankton community characteristics in these semiarid waters. The Arabian Gulf receives seasonal freshwater discharge in the north via Shatt Al-Arab estuary with a peak during March-July. A north to south gradient in the proportion of the freshwater exists between station A in the vicinity of Shatt Al-Arab estuary and station 18 in the southern offshore area. At station A, the proportion of freshwater was the highest (25.6-42.5%) in 1997 but decreased to 0.8-4.6% by 2012-2013. The prevailing hyperhaline conditions off Kuwait are attributed to decrease in the river flow. Phytoplankton data showed a decrease in the number of constituent taxa in the last one decade from 353 to 159 in the Kuwait Bay and from 164 to 156 in the offshore area. A shift in their biomass was caused by a decrease in diatom species from 243 to 92 in the coastal waters and from 108 to 83 in the offshore areas with a concomitant increase of smaller algae. Mutivariate agglomerative hierarchical cluster analysis, non-metric multi-dimensional scaling, and one-way analysis of similarity analyses on phytoplankton data at different taxonomic levels confirmed significant changes in their community organization on a decadal scale. These evidences support our hypothesis that the salinity-related environmental changes have resulted in a coincidental decrease in species diversity and significant changes in phytoplankton community between the years 2000-2002 and 2012-2013, off Kuwait. This in turn would affect the pelagic trophodynamics as evident from a drastic decrease in the catch landings of Tenulosa ilisha (Suboor), Carangoides sp. (Hamam), Otolithes ruber (Nowaiby), Parastromateus niger (Halwaya), and Epinephelus coioides (Hamoor) in Kuwait.

Individual shrink wrapping extends the storage life and maintains the antioxidants of mango (cvs. 'Alphonso' and 'Banganapalli') stored at 8 °C.

Freshly-harvested mature green mangoes (cvs. 'Alphonso' and 'Banganapalli') were individually shrink wrapped using two semi-permeable Cryovac films® (D-955 and LD-935) and a locally available LDPE film. The shrink wrapped and non-wrapped fruit were stored at 8 °C for 5 weeks and transferred to ambient conditions for subsequent ripening, to study the feasibility of alleviation of chilling injury (CI) and to determine shrink wrapping effect on fruit quality. Shrink wrapped mangoes of 'Banganapalli' and 'Alphonso' cultivars packed in D-955 (15 µm thickness) film could be stored for 5 weeks at 8 °C in fresh and unripe green condition. After storage, these cultivars respectively lost only 0.5 and 1.4 % mass in case of shrink wrapping as compared to 5.8 and 6.9 % loss in non-wrapped fruit. After removal from low temperature and unwrapping, shrink wrapped mangoes showed normal respiratory behaviour with production of CO2 and ethylene peaks (climacteric peaks) during ripening, whereas non-wrapped fruit did not show any respiratory peaks. Shrink wrapped mangoes ripened normally within a week at ambient temperature (24-32 °C and 60-70 % RH) with good surface yellow colour (reflected by hue and chroma values), edible softness, retention of nutritional quality and acceptable organoleptic quality. These quality parameters were better in fruit wrapped with D-955 film compared to LD-935 and LDPE films. Total carotenoids in terms of ß-carotene content were significantly higher in shrink wrapped fruit when compared to non-wrapped fruit. Among different shrink films, total antioxidant capacity and DPPH radical scavenging abilities were higher in LD-935 wrapped fruit in case of 'Alphonso' cultivar whereas these were on par in LD-935 and D-955 film wrapped fruit in case of 'Banganapalli' cultivar.

Effect of pretreatments and modified atmosphere packaging on the shelf life and quality of fresh- cut green bell pepper.

Present study was aimed at understanding the effect of pretreatments and modified atmosphere packaging on the quality of fresh-cut green bell pepper (Capsicum annuum L.) during low temperature storage. Dip treatment of freshly cut green bell pepper pieces in 2 % calcium propionate followed by surface drying and subsequent packing in cryovac PD961 film which maintained an equilibrium modified atmosphere of 13-14 % O2 and 7 % CO2 helped to extend the marketability till 9 days storage at 8 °C. The microbiological quality was at the best level up to 6 days of storage, as evidenced by a surge in aerobic plate count, pectinolysers and pseudomonads on subsequent days. Head space volatile analysis of the produce at regular intervals showed a reduction in monoterpenoids and simultaneous increase of aldehydes and ketones, sesquiterpenoids, esters, furans and pyrazines during storage. Principal component analysis of the head space volatiles identified, cis - ocimene, 1,3,8-paramenthatriene, trans 3- caren 2-ol, bergamotene, 2-hexenal, ethyl 1- decanol, (E)-3- hexenol and heptane thiol as the markers of freshness in minimally processed green bell pepper.

Synthesis, characterization and biological studies of substituted quinozoline-4-(3H)-ones containing diazepine moiety.

The synthesis and characterization of new series of 1,4-benzodiazepine derivatives have been presented. The structures were confirmed by elemental analyses, IR spectral, (1)H NMR spectral and mass spectral data. All the compounds were screened for in vitro antimicrobial and anthelmintic activities. The antibacterial activity was tested against Staphylococcus aureus (Gram positive), Bacillus cereus (Gram positive), Escherichia coli (Gram negative) and Pseudomonas aeruginosa (Gram negative). The antifungal activity was tested against Aspergillus niger and Candida albicans. All the compounds showed considerable antimicrobial activity against the microorganism studied. The significant anthelmintic activity of all novel compounds was demonstrated against Pheretima posthuma. Based on the nature of substituent present, the structure-activity correlation of novel compounds was discussed.

In vitro microbiological evaluation of novel bis pyrazolones.

Two series of bis pyrazolones (one with 3-methyl substituent and the other one with 3-amino substituent on the pyrazolone ring) were synthesized by the cyclization reaction between various hydrazides with esters/cyano esters in ethanolic medium. Structures of newly synthesized compounds were confirmed by elemental analysis, IR, (1)H NMR and mass spectral data. These compounds were screened for antibacterial and antifungal activities. The compounds of series 3 with amino substituent demonstrated better activity than the compounds of series 2 with methyl substituent on the pyrazolone ring. Compounds "e, f, c and d" showed higher antimicrobial activity than the compounds "b and a". The antimicrobial potentials of the synthesized compounds were compared with that of standards.

Quantitative phase microscopy using dual-plane in-line digital holography.

We present detailed theoretical evaluation and thorough experimental investigation of quantitative phase imaging using our previously demonstrated dual-plane in-line digital holographic microscopy technique [Opt. Lett. 35, 3426 (2010)]. This evaluation is based on the recording of two interferograms at slightly different planes and numerically reconstructing the object information. The zero-order diffracted wave is eliminated by using the method of subtraction of average intensity of the entire hologram, and the twin-image diffracted wave is removed by Fourier domain processing of the two recorded holograms. Experiments are performed using controlled amplitude and phase objects and human muscle cells to demonstrate the potential of this technique.

Dual-channel in-line digital holographic double random phase encryption.

We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated.

Development of paratransgenic Artemia as a platform for control of infectious diseases in shrimp mariculture.

AIM: To study the accumulation and retention of recombinant proteins in Artemia gut for optimizing paratransgenic disease control in shrimp aquaculture. METHODS AND RESULTS: Transgenic Escherichia coli expressing fluorescent marker proteins and the transgenic cyanobacterium Synechococcus bacillarus expressing a functional murine single chain antibody, DB3, were fed to Artemia franciscana. Stable expression and retention of several marker molecules (e.g. GFP, DS Red and DB3) up to 10 h after of feeding with E. coli were evident within the gut of Artemia. Engineered strains of S. bacillarus expressing DB3 accumulated within the gut of Artemia with detectable antibody activity for 8-10 h of feeding via ELISA, coincident with the time period of the highest density of transgenic S. bacillarus in the Artemia gut. CONCLUSIONS: Artemia fed transgenic bacteria or algae accumulated recombinant proteins for up to 10 h that retained biological activity. Co-delivery of multiple recombinant proteins simultaneously in the gut of Artemia was also demonstrated. SIGNIFICANCE AND IMPACT OF THE STUDY: Expression of molecules that target infectious agents of mariculture in shrimp via commonly deployed feed organisms such as Artemia could potentially offer powerful new tools in the ongoing global effort to increase food supply.

Development and validation of a highly sensitive LC-MS/MS method for simultaneous quantitation of nortriptyline and 10-hydroxynortriptyline in human plasma: application to a human pharmacokinetic study.

A highly sensitive and specific LC-MS/MS method has been developed for simultaneous estimation of nortriptyline (NTP) and 10-hydroxynortriptyline (OH-NTP) in human plasma (250 µL) using carbamazepine as an internal standard (IS). LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. A simple liquid-liquid extraction process was used to extract NTP, OH-NTP and IS from human plasma. The total run time was 2.5 min and the elution of NTP, OH-NTP and IS occurred at 1.44, 1.28 and 1.39 min, respectively; this was achieved with a mobile phase consisting of 20 mm ammonium acetate : acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a HyPURITY C(18) column. The developed method was validated in human plasma with a lower limit of quantitation of 1.09 ng/mL for both NTP and OH-NTP. A linear response function was established for the range of concentrations 1.09-30.0 ng/mL (r > 0.998) for both NTP and OH-NTP. The intra- and inter-day precision values for NTP and OH-NTP met the acceptance as per FDA guidelines. NTP and OH-NTP were stable in a battery of stability studies, i.e. bench-top, auto-sampler and freeze-thaw cycles. The developed assay was applied to a pharmacokinetic study in humans.

Identification and characterization of new impurities in rivastigmine.

Rivastigmine is a drug against Alzheimer's disease, and is a non-pharmacopoeial compound. During the preparation of rivastigmine in our laboratory, two impurities were detected and identified with a simple and sensitive reversed-phase liquid chromatography coupled with electrospray-mass spectrometry. The same impurities were also observed in commercial batches. These impurities were isolated by preparative HPLC and co-injected with rivastigmine sample to confirm the retention times in HPLC. These impurities were characterized as N,N-dimethyl-3-[1-dimethylaminoethyl]phenylcarboxylate (dimethyl-rivastigmine) and N,N-diethyl-3-[1-dimethylaminoethyl]phenylcarboxamide (diethyl-rivastigmine). Structural elucidation of these impurities by spectral data (1H NMR, 13C NMR and MS) is discussed.

Autotrophic picoplankton in the tropical ocean.

In phytoplankton of the eastern tropical Pacific Ocean from 25 to 90 percent of the biomass (measured as chlorophyll a) and 20 to 80 percent of the inorganic carbon fixation were attributable to particles that could pass a screen with a 1-micrometer pore diameter. Evidence is presented that these are indeed autotrophic cells and not cell fragments.

HANSIS software tool for the automated analysis of HOLZ lines.

A software tool, named as HANSIS (HOLZ analysis), has been developed for the automated analysis of higher-order Laue zone (HOLZ) lines in convergent beam electron diffraction (CBED) patterns. With this tool, the angles and distances between the HOLZ intersections can be measured and the data can be presented graphically with a user-friendly interface. It is capable of simultaneous analysis of several HOLZ patterns and thus provides a tool for systematic studies of CBED patterns.

Coherent population oscillations and superluminal light in a protein complex.

We observed superluminal light in aqueous solution of the protein complex bacteriorhodopsin (bR) at 647.1 nm wavelength where it exhibits reverse saturable behavior, exploiting the technique of coherent population oscillations (CPO). With a modulation frequency of 10 Hz, the signal pulse through a 1 cm path cell is ahead by 3 msec relative to the reference pulse, corresponding to a group velocity of -3.3 m/sec. Following our early work on slow light in the same sample at the saturable wavelength 568.2 nm, we now explicitly observed the narrow spectral hole in the absorption band of the stable B state and further, demonstrated a close correlation between the profile of the hole and the corresponding pulse delay for various modulation frequencies. A similar behavior is observed for superluminal light versus antihole blown in the absorption band.

A validated reversed phase HPLC method for the determination of process-related impurities in almotriptan malate API.

An isocratic reversed phase liquid chromatographic (RP-LC) method has been developed and subsequently validated for the determination of almotriptan malate and its process-related impurities. Separation was achieved with a Phenomenex, Gemini, C-18 column and sodium phosphate buffer (pH adjusted to 7.6): acetonitrile (80:20, v/v) as eluent, at a flow rate of 1.5 mL/min. UV detection was performed at 227 nm. The method is simple, rapid, selective, accurate and stability indicating. The described method is linear over a range of LOQ, 1.5 ug/mL (150% of the specification limit) for all the process-related impurities. The method precision for the determination of related compounds was below 1.0% R.S.D. The accuracy of the method demonstrated at 4 levels in the range of 25-150% of the specification limit and the recovery of impurities were found to be in the range of 96-102%. The method is useful in the quality control of bulk manufacturing.

Optical Fourier techniques for medical image processing and phase contrast imaging.

This paper briefly reviews the basics of optical Fourier techniques (OFT) and applications for medical image processing as well as phase contrast imaging of live biological specimens. Enhancement of microcalcifications in a mammogram for early diagnosis of breast cancer is the main focus. Various spatial filtering techniques such as conventional 4f filtering using a spatial mask, photoinduced polarization rotation in photosensitive materials, Fourier holography, and nonlinear transmission characteristics of optical materials are discussed for processing mammograms. We also reviewed how the intensity dependent refractive index can be exploited as a phase filter for phase contrast imaging with a coherent source. This novel approach represents a significant advance in phase contrast microscopy.