23 research outputs found
Characterization of Enzymes Produced by Bacillus species
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Effects of different drying and processing methods on vitamin C, color, phenolics, antioxidant activity, and mogroside V of Luo Han Guo (Siraitia grosvenorii) drink
No full textLuo Han Guo fruit (LHG), native to Guangxi province of China, is rich in mogrosides, polyphenols, vitamins, and many other nutrients. Drying and processing methods are known to impact the final quality of food product. In this study, traditional hot-air dried Luo Han Guo (HAD-LHG) and low temperature-vacuum dried Luo Han Guo (LTVD-LHG) fruit samples were used to make Luo Han Guo aqueous drink that was subjected to high hydrostatic pressure processing (HHPP) and thermal pasteurization. Unpasteurized LHG drinks were used as controls. Color, vitamin C, total phenolic content, mogroside V content, and cellular antioxidant activity in HepG2 cells were measured and analyzed for the LHG drinks. Results showed that pH values of original LHG aqueous drink were highly affected by the drying methods of LHG fruit. HAD-LHG drink had pH values of 4.4 - 4.8, while pH values of LTVD-LHG were around 5.8 - 6.1. No significant differences of color parameters (L*, a*, b*, C*, hue, browning index) of LHG drink were found after treated by HHPP or thermal pasteurization. Whereas color indices were greatly affected by drying methods of LHG. The color of HAD-LHG drink was dark brown, and the color of LTVD-LHG drink was light yellow. The browning index of HAD-LHG drink (199 ± 8) was much higher than that of LTVD-LHG drink (21 ± 5). Drying methods of LHG fruit largely affected their vitamin C content, total phenolic content, and mogroside V content. LTVD-LHG had much higher vitamin C content and mogroside V content than HAD-LHG, but HAD-LHG drink exhibited significantly higher total phenolic content (499 ± 114 mg GAE/100 g dried LHG) than LTVD-LHG drink (136 ± 40 mg GAE/100 g dried LHG). Drink processing methods showed no significant effects on total phenolic content and mogroside V content of each LHG drink. The cellular antioxidant activity (CAA) values of HAD-LHG drink was not significantly affected by drink processing methods. But CAA values of LTVD-LHG drink would be decreased after thermal pasteurization when comparing to high pressure processing and unpasteurized control groups.M.S.Includes bibliographical referencesby Lin J
Characterization of microbial inactivation using plasma activated water and plasma activated buffer
No full textPlasma activated water (PAW) has been shown to be a promising surface decontamination technique. Antimicrobial effects of PAW have been attributed to reactive oxygen and reactive nitrogen species, which act as oxidizing agents and also contribute to the acidifying effect, causing the pH of water to drop. To isolate the effect of low pH on microbial inactivation, a buffer with the same pH (3.1) as that of PAW was evaluated. Plasma Activated Buffer (PAB) was generated to study the interactive effects of low pH and plasma activated species. Previously, substrate properties (roughness) have been shown to affect the antimicrobial efficacy of plasma. The objectives of this research were: (1) To isolate the effect of pH in PAW using a buffer solution, (2) Characterize plasma, PAW, and PAB, and (3) To evaluate the effect of surface roughness on microbial inactivation using PAW and PAB. PAW and PAB were generated by exposing sterilized distilled water and citrate-phosphate buffer (pH = 3.1), respectively, to atmospheric pressure air plasma jet. Efficacy of distilled water, PAW, buffer, and PAB for inactivation of Enterobacter aerogenes was evaluated in a planktonic system, and for different surfaces with increasing roughness. Surface roughness (Pq) values for four sample surfaces (glass slide, grape tomatoes, limes, spiny gourd) were obtained using Confocal Laser Scanning Microscopy (CLSM). Optical Emission Spectroscopy (OES) was used to obtain an emission spectra for plasma. Electrical conductivity and Oxidation Reduction Potential (ORP) were measured for PAW and PAB. In the planktonic system for treatment time of 10 min, a (1.92 ± 0.70) log CFU/ml reduction using PAW (pH = 3.1) was achieved, however, no reduction was observed using only the buffer at the same pH. This confirmed that the inactivation was due to the reactive species in PAW, and not due to the low pH. A (5.11 ± 0.63) log CFU/ml reduction was observed using PAB in the same system, suggesting interactive effects of plasma generated species and low pH in the buffer system. In studies with glass slide, grape tomatoes, limes, and spiny gourd, it was found that as the surface roughness (Pq) value increased, the inactivation due to PAB treatment decreased. Highest reduction of (6.32 ± 0.43) log CFU/surface was achieved for glass slide (Pq = 0.28 ± 0.02 μm), followed by (5.31 ± 0.14) log CFU/surface for grape tomatoes (Pq = 5.17 ± 0.53 μm), and (3.80 ± 0.63) log CFU/surface for limes (Pq = 18.76 ± 3.00 μm). The least reduction of (2.52 ± 0.46) log CFU/surface was observed for spiny gourd, which had the highest roughness (Pq = 101.50 ± 10.95 μm). For PAW treatment, lower inactivation for each surface was observed. Moreover, no significant difference in microbial inactivation between the samples of different roughness values, was observed when treated with PAW. The ORP and electrical conductivity values of PAW and PAB showed a positive correlation with microbial inactivation in the planktonic system. Thus, PAW and PAB can potentially be used for fresh produce decontamination. However, further research is needed to confirm the suitability of PAW as an industrial sanitizer. In addition, the effectiveness of plasma activated organic acids also should be explored.M.S.Includes bibliographical referencesby Isha Josh
Efficacy and suitability of cold plasma generated novel sanitizer in egg washing
No full textSalmonella Enteritidis has been recognized as the cause of over 60% of reported salmonellosis cases, associated with shell eggs and egg products (CDC, 2013). In order to reduce occurrence of salmonellosis, egg washing on an industrial scale was mandated in some countries such as the United States of America and Japan (Hutchinson et al., 2003). Chemical sanitizers like quaternary ammonia (QA), used in commercial egg washing have been seen to cause degradation of the egg cuticle, which is a natural protectant against bacterial penetration (Bialka et al., 2004). So as to preserve the cuticle, and not compromise on microbial safety, plasma activated water (PAW) was investigated as a possible sanitizer on the basis of microbial reduction on artificially contaminated eggs, as well as its effect on the quality of cuticle and egg shell strength. PAW was generated by exposing distilled water to atmospheric pressure plasma jet from filtered dry air. PAW and QA were then used to wash eggs artificially contaminated with Enterobacter aerogenes (non-pathogenic Salmonella surrogate), to compare their effectiveness in microbial reduction on egg surface as well as in wash water. Colorimetric analysis was performed on eggs washed with sanitizers and stained with a cuticle sensitive dye, to evaluate loss of cuticle. Additionally, damage to cuticle was studied using microscopic analysis of egg shells. Damage to shell integrity was studied by means of texture analysis of sanitized eggs, to ensure that the acidic nature of PAW did not affect egg shell strength. Preliminary planktonic-cell experiments with distilled water (DW) which served as control, caused bacterial reduction of 0.2±0.1 log CFU/ml from initial concentration of 9.2±0.1 log CFU/ml. On the other hand, treatment with equal volumes of PAW or QA resulted in bacterial concentration below detection limit (3.2 log CFU/ml). This proved that microbial reduction was not due to osmotic pressure generated by water. This was further enforced by analysis of artificially contaminated shell egg surface, with an initial bacterial concentration of 7.9±0.3 log CFU/egg, sanitized with PAW, QA and DW. Upon exposure of eggs to sanitizers by massaging of egg surface, it was noted that bacterial survival after treatment with both PAW and QA was below detection limit (2.3 log CFU/egg). Thus, the microbial reduction efficiencies of PAW and QA were comparable, at over 5.3 log CFU/egg. Conversely, treatment with DW showed survival of 3.7±0.1 log CFU/egg on the surface of egg. Colorimetric analysis showed statistically significant difference between un-sanitized farm eggs, and farm-eggs treated with PAW and, QA and store-bought eggs suggesting that eggs treated with PAW retained their cuticle layer better. Texture analysis of treated whole eggs revealed that the acidic nature of PAW did not affect the peak force needed to crack eggs. Eggs sanitized with both QA and PAW showed highest peak strength at the small-end up position and lowest peak force at the equatorial positions. A significant difference was observed between the orientations of eggs; however, the difference in strength within a given orientation, among different sanitizing treatments was not significant. This study showed that PAW possessed both comparable anti-microbial efficacy and effect on egg shell strength as QA, while being better at cuticle retention on shell egg surface. QA was observed to erode the cuticle layer, while similar treatment with PAW showed that the cuticle coverage was relatively intact and comparable to unsanitized eggs. Thus, PAW appeared to show promise for use in egg washing process to replace current chemical sanitizers (QA) with minimal cuticle loss.M.S.Includes bibliographical referencesby Shruthi Lakshmi Narasimha
Mild heat and ultraviolet radiation in sequence to inactivate alicyclobacillus acidoterrestris spores in apple juice
No full textMild heat followed by UV treatment was investigated in this study on apple juice inoculated with the spores of Alicyclobacillus acidoterrestris. Commercially pasteurized apple juice was inoculated with the spores of Alicyclobacillus acidoterrestris and subjected to mild heat treatment to ensure at least 90 % spore germination. The juice was then subjected to UV-C light of intensity between (1.4-1.6) mW/cm2 for various times between 10 s to 600 s. A 4.2 log reduction was obtained upon combined heat treatment at 52 °C for 38 min followed by UV-C treatment of (1.4-1.6) mW/cm2 for 60 s. This treatment was compared with commercial pasteurization by head space GC-MS analysis for volatile fraction in apple juice and sensory evaluation of taste, color, and smell. Our results indicated that the quality attributes did not change due to combined heat and UV-C treatment of the commercially pasteurized juice.M.S.Includes bibliographical referencesby Vahini Manivanna
Effect of extrusion on physico-chemical properties of quinoa-cassava extrudates fortified with cranberry concentrate
No full textExtrusion is one among the major technologies used in food manufacturing. When extrusion is used to make puffed products such as breakfast cereals, it is a high temperature short time process, in which high shear and heat are applied on low moisture feed. During extrusion of cereal based food materials, several molecular transformations such as starch gelatinization and protein denaturation occur, leading to changes in the physico-chemical properties of the extrudates. The major objectives of this study were to make extruded ready-to-eat (RTE) breakfast cereal from quinoa, fortified with cranberry concentrate and to study the effect of extrusion on the physico-chemical properties of the extrudates. Cassava flour was used as an extrusion aid for puffing. The base feed consisted of 50-50 blend of quinoa and cassava. Phenolic rich cranberry concentrate had anthocyanins which acted as natural colorants for the extrudates. A single screw extruder equipped with a 4:1 compression ratio screw, set at 130 RPM, was used with a 4.5 mm diameter die hole. A 3^3 Box- Behnken Design was used to design the experiments for three independent variables: barrel temperature (120 ˚C, 140 C, 160 ˚C), cranberry solids (3 %, 4 %, 5 % (d. b.)), and feed moisture (16 %, 18 %, 20 % (w.b.)). Physical properties such as Radial Expansion Index (REI), Bulk Density (BD), Breaking Strength (BS), Hue, Chroma, Water Absorption Index (WAI), and Water Solubility Index (WSI) along with chemical properties such as Total Phenolic Content (TPC) and anthocyanin content were evaluated. Extrudates collected at barrel temperature of 160 ˚C, 16 % feed moisture and 4 % cranberry solids showed lowest Bulk Density of 0.281 g/ml and Breaking Strength of 0.46 N/mm2. From the response surface analysis, it was found that barrel temperature and feed moisture were the two most important variables that affected the physical properties. The TPC of extrudates collected at higher barrel temperatures were found to contain higher phenolic values (~ 80 mg GAE/100 g d.m.), probably due to the formation of Maillard products. Extrudates collected under 140 ˚C barrel temperature, 16 % feed moisture and 5 % cranberry solids showed maximum anthocyanin content of 9.63 mg / kg d.m. This study will open new avenues to develop gluten free extruded products that can be naturally colored with antioxidant loaded fruit concentrates.M.S.Includes bibliographical referencesby Soundharya Chandra
Modeling bacteria-produce interaction during washing: effect of shear stress
No full textDue to increase in health awareness, there is an increase in the demand for fresh produce. The consumption of fresh produce has increased over the last few years. Most of the fresh produce is consumed raw or without any major processing steps before consumption. According to CDC report (2015 CDC annual report), more than 26% of the reported illnesses were associated with fresh produce. Safety of fresh produce is recognized as one of the significant challenges by the US Food and Drug Administration (FDA, 2015). Maintaining freshness, safety, and high-quality of fresh produce is essential for the industry to meet consumer demand. Physical and chemical methods are commonly used for bacterial removal and inactivation during produce washing. While chemical methods are widely studied, a few studies show that shear stress has a significant effect on bacterial removal during produce washing. In this study, a numerical approach was used to understand the effect of shear stress on the attachment of bacteria to produce surface and the detachment of bacteria from a fresh produce surface. COMSOL® Multiphysics was used to simulate turbulent flow in an experimental benchtop washing device to understand the effect of shear stress on (a) the detachment of bacteria from produce surface to wash water and (b) the attachment of bacteria to produce surface from wash water containing contaminated organic load. A 2D axisymmetric k- turbulent flow model with swirl flow was used in the numerical simulation. The geometry consisted of a downward facing rotating disk with a produce leaf attached at the center of the disk, in a tank filled with water. Single phase flow and a two-phase flow were simulated for detachment and attachment studies, respectively. The flow profiles and velocity vectors of the turbulent flow were obtained using numerical simulation. Shear stress distribution along the radius of the leaf was calculated numerically. The results showed that the average shear stress exerted on the leaf surface was 28.3 mPa and 109 mPa, at 100 rev/min and 200 rev/min, respectively. Experimental results (from UC Davis) showed that the corresponding detachment of bacteria was about 1 log CFU/cm2 and 1.5 log CFU/cm2, respectively. In the attachment studies involving a two-phase flow of wash water and simulated organic particles, numerically predicted average shear stress values were 137 mPa and 403 mPa, at 100 rev/min and 200 rev/min, respectively. Predicted shear stress values were higher due to the suspended particles (beads). Experimental data showed that some (up to 0.4%) bacteria from the beads got transferred to the leaf surface suggesting that attachment can take place in the presence of shear stress. The point-attachment model using ordinary differential equations to describe the ligand-receptor binding of bacteria and produce surface was used to quantify the detachment and attachment of bacteria from produce surface as a function of time. In the mathematical model that we developed, shear and sanitizer concentration were included. MATLAB® was used to numerically solve the differential equations to study of the effect of detachment rate constant and the presence of sanitizers on the removal and transfer of bacteria. The detachment rate constant is effective in mediating the detachment and attachment of bacteria, in the absence of sanitizers in water. Nevertheless, the effect of detachment rate constant is shown not to be significant in the presence of a sanitizer during washing of produce. Understanding the effect of shear stress on microbe - produce interaction will help improve the design of wash water systems and minimize the probability of cross contamination during washing process for fresh produce.M.S.Includes bibliographical referencesby Yuyang Tia
Diplectrona marginata
No full textDiplectrona marginata (Betten 1909) (Figs 6–20) Hydromanicus marginatus Betten 1909: 236–237, plate 15 fig. 13; syntypes 2 females: Kurseong [West Bengal], Annandale, May 1906; deposited in the Indian Museum [NZC], Kolkata, India. Diplectrona marginata (Betten 1909); Martynov (1935: 181–182, text figs 83, 84a–84c), new combination, male described; Gosh & Chaudhury (1998), reported from India (Himachal Pradesh, Uttar Pradesh, West Bengal); Malicky (2002), discussed identification problems. D. kinulta Oláh et al. 2020: 160–161, figs 23–27; holotype male: China, Tibet, Muotuo [county], 80K 1000 m, 24.vii.2012, leg. Li Wen-liahng; deposited in the Entomological Museum of China Agricultural University, Beijing; NEW SYNONYM. Neotype. We designate a neotype for D. marginata (Betten 1909). One of the 2 female syntypes from India [Kurseong, West Bengal, collected by Dr Nelson Annandale, in May 1906] is missing from the NZC and is probably destroyed. The senior author himself examined the remaining one of these syntypes which is in very bad condition without head and with damaged wings, although the abdomen is intact. Another set of specimens from the Indian Himalayas (Martynov 1935: 181) was assigned to D. marginata and a male was described by Martynov (1935). The original description of the species is ambiguous and incomplete, creating confusion and uncertainty about the identity of this species and its distinction from other species (Schmid 1961: 201; Malicky 2002: 1214). Females of this genus are very similar and diagnostic characters for distinguishing them are subtle or unknown (Ito & Nozaki 2018; Mey 1999; Neboiss 2002; Wells & Neboiss 2018). Therefore, although Malicky (2002) recommended that the name Diplectrona marginata should be treated as a nomen dubium, we prefer to select a neotype from among a series of specimens in the Indian Himalayas (Martynov 1935: 181–182) and conforming with the limited details of the original description, thereby “clarifying the taxonomic status” of the species (International Code of Zoological Nomenclature 1999, Article 75.1). The specimen selected here is said by Martynov (1935) to “represent a mountain form of the species.” Material examined: Neotype: Male. India: Collection Label Verbatim: Punjab, Ghuma, Simla Hills, 3760 ft., 6–8-ix-1925, B. Chopra; Interpretive data: Himachal Pradesh, Shimla Hills, Gumma Village (Ghuma of Martynov), 1520 m, 6–8-ix-1925, B. Chopra (NZC). Additional Material: Himachal Pradesh, Shimla Hills, Gumma Village (Ghuma of Martynov), 1520 m (as per interpretive data), 6–8-ix-1925, Chopra, (NZC), 4 males. Uttarakhand, Dehradun, Jhabarkhet (on Mussoorie-Tehri Road), 1300 m, 20–25-vi-1930, Chopra, (NZC), 1 male, 1 female (damaged). Mandal, 1700 m, 14-vi-2009, Pandher & Parey, (NPC), 1 male, 1 female. West Bengal, Kurseong, 1500 m, 17-vi-1910, Annandale, (NZC), 1 male, 1 female; Darjeeling, 2000 m, (no date is mentioned on label), Lynch, (NZC), 1 female. Diagnosis. The male genitalia of D. marginata, in the shape of the lateral lobes of tergum X, are similar to D. jacobsoni Malicky and Chantaramongkol 2002 and D. pachalatkoi Malicky 2009. However, the mesocaudal lobes of tergum X are fused half their length, slender basally, broad apically, mesoapically pointed, narrowly separated apically in dorsal view in D. marginata; whereas the mesocaudal lobes of tergum X are broad at their base and separated apically in D. jacobsoni and the mesocaudal lobes of tergum X are fused, broad at their base and rounded apically with a narrow mesal separation in D. pacholatkoi. Furthermore, in D. marginata, the lateral lobes of tergum X are more divergent than in those species and a small inner lobe-like structure (or fold) is visible on the mesal margins of the lateral lobes of tergum X in dorsal and lateral views in D. marginata, a unique characteristic for this species. Drawings of genitalia of three other specimens are provided to show variation. These were redrawn to show the variation in the lateral lobes of tergum X which might be seen on opposing lateral lobes even in genitalia of the same specimen. For example, Fig. 19 generally agrees with fig. 24 of Oláh et al. (2020) in dorsal view. These are shown to justify our conclusion that this species is widely distributed with local variation and complexity or adaptive traits based on morphology. Redescription of adult male. Color in alcohol light brown, maxillary palp infuscate, legs and antennae pale yellow, dorsum of head dark brown, no setae or hairs visible on eyes. Length from tip of head to apices of folded forewings about 7.25 mm; maxillary palps each about 1.75 mm long, segment V longest; labial palps small, each 0.50 mm long. Length of each forewing about 6 mm; venation typical for genus; discoidal cell small; forks II and III petiolate, Cu 2 and A curved. Hind wings each 5.25 mm long, broad; Sc very thick; R1 fine and sinuate, fork I present. Gland on V sternum visible, filament directed posterad, length of filament more than 1.5x but less than 2x sternite length. Male genitalia (Figs 6–20). Abdominal segment IX annular; anterolateral margins convex, angled at anterior ends of pair of internal longitudinal carinae above middle; posterior margins irregular, produced slightly over bases of inferior appendages. Tergum X divided into pairs of mesocaudal lobes and lateral lobes; mesocaudal lobes fused, apically separated for short distance, blunt apicomesally, longer than lateral lobes; lateral lobes covered basally by broad and setose preanal appendages, broad basally and divergent with distal margins curved laterad, pointed, each with small sclertotized fold on mesal surface. Preanal appendages paired, broad, with prominent large setae visible both in lateral and dorsal views. Inferior appendages each 2-segmented; basal segment long, extending beyond mesocaudal lobes of tergum X, broad basally and apically in lateral view, slightly constricted and with slight bend dorsad near base, in ventral view abruptly curved mesad preapically; apical segment broad at base, 1/3 as long as basal segment in lateral view, curved mesad in ventral view and sharp apically. Phallus, tubular, slightly angled ventrad near base, with one pair of elongate spines and ventral scoop-like structure apically; phallicata complex and with pair of long, semicircular sclerotized ventral lobes in ventral view. Recently, Oláh et al. 2020 described D. kinulta from Tibet, mentioning in the diagnosis that this species is similar to D. burha because both of these species have subquadrangular, plate-like paraprocts (lateral lobes of tergum X) with variously divergent apical patterns. They did not mention D. marginata but observed that the male of D. kinulta differs from that of D. burha by the character combination of small seta-less eyes, a pair of large internal sacs in segment VIII, long posteroventral filaments on sternite V (2.24 times as long as the sternite), fork I on the hind wings, elongate lobes of segment X; and a deltoid head of the phallic organ. In contrast, the male of D. burha is characterized by lateral filaments of segment V that are 1–2 times as long as the segment, small internal glands of segment V, absence of internal glands of segment VIII, and a different shape of the genitalia (Malicky 2002; Ito & Nozaki 2018: 547, figs 2A, 2B). The male genitalia of D. burha are distinguished from those of other congeneric species (including D. marginata) mainly by large preanal appendages (p.a.) and segment X having each subquadrate lateral lobe often with a depression in the apical margin in dorsal aspect and its well-developed mesocaudal lobes (m.c.l.) are separated by a narrow mesal slit in dorsal aspect (Malicky 2002: pl. 14; Ito & Nozaki 2018: 547, fig. 2C). According to Oláh et al. (2017, 2020), the paraprocts are an extremely stable and invariant organ in a species but differing among species, including those in Diplectrona. Paraprocts act as titillating or stimulating organs of the genitalia, typically formed by an adaptive mechanism, and are a stable genetic component compared to the variable neutral organs under the influence of stochastic events. They (2020) conclude that Diplectrona is very diverse in southern Asia, with several species complexes currently identified as a single species, complexes they purport to be best analyzed with “fine phenomics.” The remaining questions and the validity of their research program, of course, can be addressed in future research based on population samples, molecular studies, and more care with a research focus on adaptive speciation traits. In the meantime, based on the observed morphological similarity, we consider D. kinulta a synonym of D. marginata. Distribution. India (West Bengal, Himachal Pradesh, Uttarakhand), China (Tibet).Published as part of Pandher, Manpreet Singh, Kaur, Simarjit, Garima, Deepti & Parey, Sajad H., 2021, Genus Diplectrona Westwood 1840 (Insecta: Trichoptera) in India, pp. 342-352 in Zootaxa 5047 (3) on pages 345-349, DOI: 10.11646/zootaxa.5047.3.6, http://zenodo.org/record/554092
