First Report on Post-harvest management of black mold of onion by eugenol

Black mold of onion caused by Aspergillus niger is a serious and prevalent postharvest disease of onion. This problem drastically reduces the quality and marketability of onion bulbs. Conventional fungicides employed to con-trol A. niger contamination posed negative impact on human health and en-vironment and highlighted the need to discover ecofriendly management practices. In the present study we attempted to explore the use of eugenol for the management of black mold of onion. Eugenol may exhibit differ-ences in antifungal activity in liquid state and in volatile phase. Hence, we developed and validated a new method, conical flask- paper cone method to study the antifungal activity of vapour phase disinfectants. This method was found to be precise, reproducible, sensitive and accurate with inter-assay R.S.D < 10%, intra-assay R.S.D <5% and R2>0.99. Conical flask- paper cone method was further utilized to determine the minimum inhibitory concen-tration of eugenol against A. niger. We observed that 0.03355 μl / cm3 eu-genol caused invitro and invivo inhibition of A. niger. Onion bulbs that were stored by eugenol fumigation, prior inoculated by A. niger, did not develop black mold symptoms and maintained high sensory acceptability. Microscop-ic observations revealed that eugenol fumigation resulted in inhibition of spore germination, coagulation of cytoplasm, formation of large vesicles and shrinkage of A. niger mycelium. In conclusion, our study showed for the first time that eugenol fumigation significantly controlled black mold incidence during storage and maintained post harvest quality and sensory acceptance. This study also introduced a new method for evaluating antifungal activity of volatile compounds.

DEGRADATION OF AZO DYE AND ELECTRICITY GENERATION USING YEAST MEDIATED MICROBIAL FUEL CELL

In the present study, the efficiency of yeast mediated microbial fuel cell (MFC) was investigated towards degradation of Trypan blue (azo dye) and electricity generation. Five yeast strains viz. SC1, SC2, SCD1, SCD2, and SCD3 were isolated from different sources. The internal resistance of yeast isolates was tested using ferric oxide reduction method. To maximize the power density of MFC, NaCl was added to the medium and NaCl tolerance of yeast strains was tested. Among the five isolates, SC1 and SCD2 showed maximum ferric oxide reduction and NaCl tolerance. Initially, 5 % of SC1 and SCD2 yeast culture were inoculated in wastewater containing azo dye (100 µg/ml) in a H-type MFC chamber and 250 ml conical flask used as a control. Increased growth of yeast strain in MFC chamber was noted compared to conical flask culture. The data of electricity generation was taken for 15 days and electricity generation was measured using the multimeter. Maximum electricity generation was noted in SC1 (950mV) followed by SCD2 (750mV). In addition, SC1 could degrade azo dye more efficiently than SCD2. Therefore, it may be concluded thatSC1 yeast mediated MFC can be used as a potential technology for electricity generation and degradation of azo dye in wastewater.

Effect of packaging material and storage conditions on potato (Solanum tuberosum L.) microtuber storability

An experiment was conducted at the ICAR-Central Potato Research Station, Gwalior (MP) during 2012-13 to study best packaging material and storage conditions for short term storage of potato microtubers of important varieties. Ten Micro tubers each of three popular varieties viz Kufri Sindhuri, Kufri Lauvkar and Kufri Chandramukhi (KCM) were packed in 5 packaging materials/ storage containers viz polythene without ventilation, polythene with ventilation, conical flask with cotton plug, conical flask with plastic cap and petri plates and kept in three storage condition viz ambient temperature, refrigerator (40C) and plant growth chamber (30C). After 45 days of storage of potato microtubers, at 5 per cent level of significance both percent overall weight loss and driage/ rottage was significantly low in polythene without ventilation (13.19 and 10.37 respectively) among packaging material and among storage conditions, at 5 per cent level of significance both percent overall weight loss and driage/ rottage was signifi-cantly low in growth chamber condition of 40C (12.77 and 12.44 respectively) over other two storage conditions. Kufri Sindhuri recorded significantly lowest overall percent weight loss (17.95) and driage/ rottage (8.00) at 5 percent level of significance over KCM and Kufri Lauvkar. Kufri Sindhuri has better storability under growth chamber condition at 30C in polythene without ventilation packaging up to 45 days.

654. A rapid method for estimating the size distribution of fat globules in cream

The proportion of fat present in cream as small globules (approximately 1 μ and under) is estimated from the proportion of the total fat which remains in the serum when a sample of the cream, diluted to 10% fat, is centrifuged at 60° C. for 30 min. at 3000 r.p.m.The fat present as large globules (7 or 8μ and over) is estimated by finding the proportion of the fat which rises 1 cm. in 60 min. when the cream, diluted to 10% fat, is held at 60° C. in a modification of the Andreasen particle-size apparatus in which the jar is replaced by a conical flask and the tip of the sampling pipette is held 1 cm. from the flat bottom of the flask.The thanks of the author are due to Dr F. H. McDowall for helpful advice and criticism and to Miss R. P. Johnson for assistance with the experimental work.

Semi-Ebonite. Part 2

In Part 1 (Rubber Chem. and Tech., 8, 554 (1935)) frequent reference was made to the volatile products emitted during the aging of semi-ebonite under different conditions. In this section an experiment is described wherein the various products were detected and some attempt made to estimate the relative amounts of each. The experiment in its original form presented considerable difficulty, and many disappointments were experienced before a modified apparatus was finally adopted. Experimental Method.—Eight test-pieces, one from each of the accelerated cures (see Part 1), were cut to a convenient size, six inches by one inch. The test-pieces were carefully weighed and their thickness determined as the average of several readings on the micrometer. The strips were suspended from a bent glass rod projecting from a cork-bearing inlet and outlet tubes (see Fig. 5). The cork was then inserted in a clean conical flask and the latter sealed with wax until it withstood a considerable vacuum. The flask was placed in a Geer oven automatically maintained at 70° C. The outlet tube was attached to an absorption train and the inlet tube to a purifying train.

II. A new method for determining the number of micro-organisms in air

This is a modification of Hesse’s well-known process. It consists essentially in the substitution of a flat-bottomed conical flask for a Hesse’s tube. Its chief advantages are:-