Elucidalion the changes in pectic substances and Ca, Mg content in relation to its hardness during maturation. Mume fruit (Japanese Apricot, Prunus Mume Sieb. et Zucc. var. microcarpa Makino) was investigated Research was carried out for about one month from May 21st to June 26th 1984 at four storage temperatures, 3°C, 15°C, 30°C and 35°C.
The following results were obtained.
1) The hardness of the fruit was seen to decrease with the fruit growth. Observations were conducted on the increase of WSP (water-soluble pectin), the decrease of HSP (hydrochloric acid-soluble pectin) and HSP/WSP ratio.
2) The total content of Ca in the pectin decreased with the fruit growth, just as the changes in the hardness and pectin content.
3) The Ca content (mg/g in PSP [hexametaphosphate-soluble pectin]) during fruit growth was also parallel to the changes in fruit hardness.
4) The fruit became softer during the storage period as the WSP increase and the HSP decrease and with the ratio of HSP/WSP. On the other hand, there was negligible change in Ca content (mg/g in each pectin fraction) during that time.
5) The Ca and Mg content (mg/g in PSP and WSP) were seen to decrease with storage. Pectin was observed to be soluble in water and hardness to increase.

View full abstract

Effect of corrugated shipping container with polyethylene laminated liner (30μm in thickness) on quality stability of broccoli (Brassica oleracea var. italica) buds was investigated during storage at 20°C, compared with usual corrugated shipping container as control. In the usual container as control, the yellowing and wilting of broccoli buds occurred after storage of 2 days. On the other hand, the container with polyethylene laminated liner kept quality of broccoli buds for 3 days even at 20°C. The decrease of levels of chemical components, including chlorophyll, total sugar and ascorbic acid, in the container with polyethylene laminated liner was also less than that in usual container. The concentrations of carbon dioxide and oxygen in the container with polyethylene laminated liner during storage were 5-10% and 6-16%, respectively, suggesting that the quality maintenance of broccoli buds in this container with polyethylene laminated liner was ascribed to modify atmosphere effect.

View full abstract

In order to evaluate the validity of the differently permeable films which are called “kinosei films” including LDPE films (40-47μm) containing porous powders of minerals (zeolite, Ag⁺ absorbed zeolite, cristobalite), ceramics and cyclodextrin, for packaging shredded vegetables, permeability of the films, changes in gaseous concentration in the bags packed with different films and microbial growth in the shredded cabbage in the bags were investigated in comparison with ordinary LDPE film (40μm) and EVA film (30μm) during storage at 20°C. (1) The highest permeability of CO₂ and C₂H₄ was found in the EVA film and the lowest permeability was found in the ordinary LDPE film and LDPE film containing Ag⁺ absorbed zeolite among the used films in this experiment. The gaseous permeability of “kinosei film” was found to be higher than that of ordinary LDPE film. (2) There was a relatively close relation between the concentration of CO₂ and C₂H₄ in the bags in which shredded cabbage (2×2cm, 30pieces) was packed with different films and the permeability of CO₂ and C₂H₄ of the films. No specific property to absorb C₂H₄ was found in the “kinosei films”. (3) There was significant difference at 5% level in the microbial counts between shredded cabbage packed with antimicrobial films and with ordinary film. However, this inhibition of microbial growth seemed to be not enough to affect keeping quality of shredded cabbage.

View full abstract

To investigate the heat transfer phenomena for a food package in a refrigerated room with upflow or downflow, temperature distributions in the package were numerically calculated using fundamental equations. These equations were derived under certain assumptions in the case where one side wall of the package was in touch with the duct and gas flowed upward or downward through the duct, while the other side walls were insulated as a model of the package wall in the refrigerated room. The temperatures were solved for an unsteady state using the empirical equation for the heat transfer coefficient.
The temperature at the front surface of the package remarkably decreased in the beginning and then only slightly decreased with elapsed time. The average heat transfer rate from the package to ambient fluid in upflow was about two times larger than the one in downflow. This meant that the cooling time of the package by upflow could be shortened by half of the downflow one.
To check these calculated results, the temperature distributions were experimentally measured under the same operating conditions as those of the theoretical analysis. The calculated temperature distributions agreed closely with the measured ones.

View full abstract

Concentrations of culture solution in hydroponics were changed for the purpose of improving the quality of herbs. Culture solution containing Ca (NO₃) ₂· 4H₂O : 45g, KNO₃ : 36g, MgSO₄· 7 H₂O : 22.5g, NH₄H₂PO₄ : 6.75g, and Fe-EDTA : 6.67g in 45l water was defined as 1 unit solution.
Japanese honewort (Cryptotaenia japonica Hassk) and hyssop grown with 1 unit solution showed higher contents of ascorbic acid (ASA), free amino acid, and chlorophyll than those grown with 2/3 unit, and they showed higher growth.
Lowering the concentration of solution to 2/3 unit resulted in the increase of growth of peppermint, sage, basil, and perilla (Perilla frutescens Britton) and the decrease of ASA and chlorophyll contents. Shelf lives of herbs with 2/3 unit were longer than those with 1 unit. The smell of herbs tested in this experiment was not affected significantly in sensory test and gas chromatography by the change of concentration of solution.

View full abstract