Leafy Brassica Research Articles

A study of the quality factors affecting the short‐term decomposition of field vegetable residues

AbstractExperiments were carried out to characterise the composition and decomposition of 13 vegetable crop residues. There was a considerable range of composition, with 55% of the dry matter being water‐soluble in onion compared with only 15% in wheat. The range of carbon/nitrogen ratio in the vegetable crops was narrow, between 9 and 24, compared with a C/N ratio of 58 in wheat. The decomposition of the residues could be described by the single‐exponential equation Y = a + be−k(t − d), where Y is the proportion of residue remaining at any thermal time day degrees above 0 °C, a is the proportion of residue remaining at the end of the experiment, b is the corresponding proportion of the degradable fraction, k is the rate constant for the decomposition process and d is a delay factor (in units of thermal time) which delays the start of the decomposition process. Y, a and b are all expressed as percentages on a weight basis and, by definition, a + b must equal 100 at t = 0. The value of d is assumed to equal zero for all residues except those from leafy brassicas, for which it was set at 100. The half‐life of crop residue decomposition ranged from 145 day deg for onion to over 1400 day deg for wheat. The decomposition rate constant (k) was related to the C and N contents (r = 0.84, p = 0.001), and the a parameter to the crop's lignin content (r = 0.74, p = 0.004).© 2001 Society of Chemical Industry

Chlorogenic acids and other cinnamates - nature, occurrence and dietary burden

This review defines the range of forms in which cinnamates (p-coumarates, caffeates, ferulates and sinapates) occur in foods and beverages subdividing them into (i) the classic chlorogenic acids and close allies, (ii) other esters, amides and glycosides, and (iii) transformation products formed during processing. Cinnamate derivatives which would not release cinnamic acid by hydrolysis are excluded. The quantitative data are reviewed concisely and attention is drawn to certain shortcomings, in particular a complete absence of data for certain commodities (breakfast cereals, baked goods, tomato products and nuts) and minimal data for pulses, legumes and processed or cooked foods. In addition, more data are required for the edible portion of modern varieties. By extrapolating from such data as are available the important source(s) (i) of individual cinnamates (regardless of the conjugate type) and (ii) of each major class of conjugate, have been identified as follows: (i) Cinnamates: caffeic acid: coffee beverage, blueberries, apples, ciders; p-coumaric acid: spinach, sugar beet fibre, cereal brans; ferulic acid: coffee beverage, citrus juices, sugar beet fibre, cereal brans; sinapic acid: broccoli, kale, other leafy brassicas, citrus juices. (ii) Conjugates: caffeoylquinic acids: coffee beverage, blueberries, apples, ciders; p-coumaroylquinic acids: sweet cherries; feruloylquinic acids: coffee beverage; tartaric conjugates: spinach, lettuce, grapes and wines; malic conjugates: lettuce, spinach, possibly legumes; rosmarinic acid: culinary herbs, mixed herbs, possibly stuffings; cell wall conjugates: spinach, sugar beet fibre, cereal brans. It seems likely that the UK population will fall into several categories depending on (i) their consumption of coffee, (ii) their consumption of bran, and (iii) their consumption of citrus. Those who drink several cups of coffee per day augmented by bran and citrus might easily ingest 500–800 mg cinnamates (or even 1 g for the greatest coffee ingest consumption) whereas those who eschew all these and take little fresh fruit or vegetables might struggle to consume 25 mg. © 1999 Society of Chemical Industry

Chlorogenic acids and other cinnamates – nature, occurrence and dietary burden

This review defines the range of forms in which cinnamates (p-coumarates, caffeates, ferulates and sinapates) occur in foods and beverages subdividing them into (i) the classic chlorogenic acids and close allies, (ii) other esters, amides and glycosides, and (iii) transformation products formed during processing. Cinnamate derivatives which would not release cinnamic acid by hydrolysis are excluded. The quantitative data are reviewed concisely and attention is drawn to certain shortcomings, in particular a complete absence of data for certain commodities (breakfast cereals, baked goods, tomato products and nuts) and minimal data for pulses, legumes and processed or cooked foods. In addition, more data are required for the edible portion of modern varieties. By extrapolating from such data as are available the important source(s) (i) of individual cinnamates (regardless of the conjugate type) and (ii) of each major class of conjugate, have been identified as follows: (i) Cinnamates: caffeic acid: coffee beverage, blueberries, apples, ciders; p-coumaric acid: spinach, sugar beet fibre, cereal brans; ferulic acid: coffee beverage, citrus juices, sugar beet fibre, cereal brans; sinapic acid: broccoli, kale, other leafy brassicas, citrus juices. (ii) Conjugates: caffeoylquinic acids: coffee beverage, blueberries, apples, ciders; p-coumaroylquinic acids: sweet cherries; feruloylquinic acids: coffee beverage; tartaric conjugates: spinach, lettuce, grapes and wines; malic conjugates: lettuce, spinach, possibly legumes; rosmarinic acid: culinary herbs, mixed herbs, possibly stuffings; cell wall conjugates: spinach, sugar beet fibre, cereal brans. It seems likely that the UK population will fall into several categories depending on (i) their consumption of coffee, (ii) their consumption of bran, and (iii) their consumption of citrus. Those who drink several cups of coffee per day augmented by bran and citrus might easily ingest 500–800 mg cinnamates (or even 1 g for the greatest coffee ingest consumption) whereas those who eschew all these and take little fresh fruit or vegetables might struggle to consume 25 mg. © 1999 Society of Chemical Industry

Study of the disappearance of endosulfan, parathion, trichlorfon and pirimicarb from broccoli and portuguese cabbage

AbstractThe influence of surface of exposure of brassicas to insecticide sprays has been assessed in two experiments conducted in small plots where endosulfan, parathion, trichlorfon and pirimicarb were applied to a flowering brassica, broccoli (Brassica oleracea L. var italica Plenck) and to a leafy brassica (Brassica oleracea L. var. tronchuda Bailey).The differences of surface exposure resulted in much higher deposits and subsequent residue levels in broccoli. The results stress the need to evaluate residue data on groups of brassicas of different surfaces of exposure to pesticide spray when granting registration petitions for brassicas in general in order to establish pre‐harvest intervals.

Dimethyl disulphide in the blood of cattle fed on brassicas.

AbstractDimethyl disulphide (DMDS), the main cause of brassica anaemia in ruminant animals, was determined in the blood of steers ingesting S‐methylcysteine sulphoxide (SMCO) present in leafy brassicas. Blood samples were treated with Zn and dilute phosphoric acid and the DMDS reduced to methanethiol which was determined by gas chromatography headspace analysis. DMDS levels increased as the intake of SMCO with the brassicas progressed. They were maximal at the haemolytic crisis; thereafter, with the appearance of young red cells or reticulocytes, they declined sharply, but again increased as the new cells matured. The distribution of DMDS was; red cell 85%, plasma 15%. The distribution reached equilibrium in vitro in about 2 h.

British Food Journal Volume 79 Issue 3 1977

One of the most serious problems facing the country today is maintaining dietary standards, especially in the vulnerable groups, in the face of rising food prices. If it were food prices alone, household budgetry could cope, but much as rising food prices take from the housewife's purse, rates, fuel, travel and the like seem to take more; for food, it is normally pence, but for the others, it is pounds! The Price Commission is often accused of being a watch‐dog which barks but rarely if ever bites and when it attempts to do this, like as not, Union power prevents any help to the housewife. There would be far less grumbling and complaining by consumers if they could see value for their money; they only see themselves constantly overcharged and, in fact, cheated all along the line. In past issues, BFJ has commented on the price vagaries in the greengrocery trade, especially the prices of fresh fruit and vegetables. Living in a part of the country given over to fruit farming and field vegetable crops, it is impossible to remain unaware of what goes on in this sector of the food trade. Unprecedented prosperity among the growers; and where fruit‐farming is combined with field crops, potatoes, cabbage, cauliflower and leafy brassicas, many of the more simple growers find the sums involved frightening. The wholesalers and middle‐men are something of unknown entities, but the prices in the shops are there for all to see. The findings of an investigation by the Commission into the trade, the profit margins between wholesale prices and greengrocers' selling prices, published in February last, were therefore not altogether surprising. The survey into prices and profits covered five basic vegetables and was ordered by the present Prices Secretary the previous November. Prices for September to November were monitored for the vegetables—cabbages, brussels sprouts, cauliflowers, carrots, turnips and swedes, the last priced together. Potatoes were already being monitored.

Magnesium deficiency in vegetable crops. A survey in Fujimi-mura and Showa-mura, Yamanashi Prefecture

In those several years, vegetable crops production in Fujimi-mura and Showa-mura near Kofu, Yamanashi Prefecture has been threatened by a nutritional disorder, which seemed to be magnesium deficiency. The authors surveyed the symptoms and distribution of the disorder in vegetable crops in the area and attempted to elucidate its cause by chemical analysis of plants and soils. The disorder was found in many sorts of vegetable, such as tomatoes, egg-plants, peppers, cucumbers, melons, snap beans, radishes, chinese ca-bbages and leafy brassicas. Fruit trees and field crops also suffered from similar disorder in this area. The general symptoms were chlorosis of in-terveinal portions of lower leaves, subsequent ne-crosis of the chlorotic area, and in some crops premature defoliation. Yields were markedly reduced in severe cases. Those symptoms were very similar to the symtoms of magnesium deficiency artificially induced in sand culture in our laboratory or reported by other investigators. Further-more, low magnesium content in the affected tomato and egg-plant leaves, and low exchangeablemagnesium content in the soils, proved that the disorder was due to magnesium deficiency. Mg content was 0.35% or less in the affected tomato leaves, and was 0.25% or less in the affect-ed egg-plant leaves. Soils in the area were sandy, or gravelly and were very low in clay and organic matter content. Soil pH was from 5.09 to 7.95. Exchangeable capacities were generally low: most of them were 5_??_7m.e., but some of them were below 5m. e. per 100g soil. Exchangeable magnesium contents of deficient soils were less than 0.5m.e. per 100g soil. No case of magnesium deficiency due to high level of potassium was found. From those results, it was clear that the magnesium deficiency of the vegetable crops in this area was due to low content of available magnesium in the soil. As control measures, soil and foliar applications of magnesium compounds were discussed. There were differences among vegetable crops in susceptibility to magnesium deficiency. Furthermore, varietal difference was found in resistance to the disorder in some crops.