A comparison of the chemical flavour composition of some brussels sprouts cultivars grown at different crop spacings

Variations in the chemical flavour composition of six cultivars of Brussels sprout were determined for plants grown at three different crop spacings (30, 45 and 60 cm from nearest neighbours). Appreciable variations in the chemical composition of the flavour extracts were observed and it was possible to distinguish the better flavoured cultivars in all cases. In general, flavour strength increased the closer together the plants were grown. The results indicate a crude yet simple method for the production of Brussels sprouts of varying flavour and flavour strength.     

The effects of different horticultural practices on the chemical flavour composition of some cabbage cultivars

Variations in the chemical flavour composition of three cultivars of cabbage were determined for plants of different horticultural histories. In some i     

Wie der Mensch zum Zucker kam

How sugar came to man Sucrose is a disaccharide, which is normally not stored in plants with a few exceptions, namely sugar beet and sugar cane. Both are economically significant plants which supply approximately 180 million tons of sugar per year. 70 per cent of the world's sugar production comes from sugar cane, which grows only in tropical and subtropical regions, and has a history of about 3,000 years. The concentrated, dried and pulverized cane sap (raw sugar) contains the most minerals, but has a strong flavour and is not universally applicable.     

The enzymic and chemically induced decomposition of glucosinolates

While the myrosinase-glucosinolate system has been reviewed in recent years by a number of authors, little attention has been paid to the enzymic and non-enzymic degradation of glucosinolates. Non-enzymic degradation processes are particularly important in the processing of brassica vegetables with respect to both flavour and in the role of glucosinolates as precursors of anticancer compounds in the diet. This review highlights early empirical work on glucosinolate degradation along with more recent aspects related to current research on mechanism of glucosinolate degradation in plants, microbes and animals.     

Microbial production of natural raspberry ketone

Raspberry ketone is an important compound for the flavour industry. It is frequently used in products such as soft drinks, sweets, puddings and ice creams. The compound can be produced by organic synthesis. Demand for "natural" raspberry ketone is growing considerably. However, this product is extremely expensive. Consequently, there is a remaining desire to better understand how raspberry ketone is synthesized in vivo, and which genes and enzymes are involved. With this information we will then be in a better position to design alternative production strategies such as microbial fermentation. This article focuses on the identification and application of genes potentially linked to raspberry ketone synthesis. We have isolated candidate genes from both raspberry and other plants, and these have been introduced into bacterial and yeast expression systems. Conditions have been determined that result in significant levels of raspberry ketone, up to 5 mg/L. These results therefore lay a strong foundation for a potentially renewable source of "natural" flavour compounds making use of plant genes.     

Plants and People in the Isle of Man,AD 800–1800

Summary

Aspects of the relationship between plants and people on the Isle of Man are discussed. They include the gradual felling of Man's woodlands, and the survival of pockets of the original woodland flora; plants with magical and ritual uses, especially those with calendar associations such as the ‘herbs of St John’ and plants associated with Tynwald Day and Lammas; herbs brought to Man by early Celtic monks; the secular herbal medicine tradition, particularly the activities of the Teare family of Ballawhane; and the herbal remedy revival which resulted from the influence of Methodism in the late 1770s. Details of herbs used to flavour beer are given as well as information on insular and imported dyestuffs.     

Modeling the kinetics of flavour release during drinking

Novel mathematical models for flavour release during drinking are described, based on the physiology of breathing and swallowing. Surprisingly, we conclude that most flavour molecules arriving in the nose are extracted from liquid left in the throat, after swallowing. The models are fit to real time flavour release data obtained using APCI-mass spectrometry. Before modelling, raw data are corrected for the effects of varying airflow rate, using the signal from acetone in exhaled air. A simple equilibrium batch extraction model correctly describes flavour release during the first breaths after swallowing a flavoured liquid. It shows that for eight volatiles, whose in vitro air-water partition coefficients vary by a factor of 500, the apparent in vivo air-saliva partition coefficients vary only by a factor of five. To interpret the kinetics of flavour release longer after swallowing, diffusion of flavour into the throat lining is included. This is done using a three-layer model for mass transfer in the throat. An analytical solution of this model gives good fits to typical data. These models de-couple the physiological and physico-chemical aspects of flavour release, clarifying the effect of behaviour on in-vivo flavour release.     

Proteomics as an approach to the understanding of the molecular physiology of fruit development and ripening

Fruit ripening is a developmental complex process which occurs in higher plants and involves a number of stages displayed from immature to mature fruits that depend on the plant species and the environmental conditions. Nowadays, the importance of fruit ripening comes mainly from the link between this physiological process in plants and the economic repercussions as a result of one of the human activities, the agricultural industry. In most cases, fruit ripening is accompanied by colour changes due to different pigment content and increases in sugar levels, among others. Major physiological modifications that affect colour, texture, flavour, and aroma are under the control of both external (light and temperature) and internal (developmental gene regulation and hormonal control) factors. Due to the huge amount of metabolic changes that take place during ripening in fruits from higher plants, the accomplishment of new throughput methods which can provide a global evaluation of this process would be desirable. Differential proteomics of immature and mature fruits would be a useful tool to gain information on the molecular changes which occur during ripening, but also the investigation of fruits at different ripening stages will provide a dynamic picture of the whole transformation of fruits. This subject is furthermore of great interest as many fruits are essential for human nutrition. Thus far different maturation profiles have been reported specific for each crop species. In this work, a thorough review of the proteomic database from fruit development and maturation of important crop species will be updated to understand the molecular physiology of fruits at ripening stages.     

The dynamics of the flavour precursors, the S-alk(en)yl-L-cysteine sulphoxides, during leaf blade and scale development in the onion (Allium cepa)

This study was undertaken to determine the patterns of accumulation and loss of the flavour precursors. (+) S-1-propyl-L-cysteine sulphoxide, (+) trans-S-1-propenyl-L-cysteine sulphoxide, and (+) S-1-methyl-L-cysteine sulphoxide, during the development and senescence of the leaf blades and scales of a brown onion ( Allium cepa L. cv. Pukekohe Longkeeper).
The levels of the flavour precursors were related to the ontogeny of the individual leaf blade and scale, and the ontogeny of the entire plant. Leaf blades which developed on a young or bulbing onion contained all 3 flavour precursors (total of about 50–70 mg leaf⁻¹); but as each attached scale developed, the leaf blades lost their flavour precursors. All 3 flavour precursors increased in the developing scales and decreased in the senescing scales. Leaf blades which developed on an older, ripening onion contained, and then lost, only (+) S-1-propyl-L-cysteine sulphoxide, whilst the scales accumulated only (+) S-1-propyl-L-cysteine sulphoxide; (+) S-1-methyl-L-cysteine sulphoxide and (+) trans-S-1-propenyl-L-cysteine sulphoxide were minimal. In the main scales of the onion, which did not senesce during ripening, there was a transition between these two patterns. These scales accumulated all 3 flavour precursors with (+) S-1-propyl-L-cysteine sulphoxide remaining constant at about 30 mg/scale; however there was a 10 fold loss of the other 2 flavour precursors (from 20 to about 2 mg/scale). The base plate (true stem) contained mainly (+) S-1-propyl-L-cysteine sulphoxide, which increased 5 fold in amount during bulbing. The other 2 flavour precursors were present at much lower levels.
A recycling of flavour precursors is suggested, with the leaf blades supplying flavour precursors to scales, and in turn older senescing scales recycling their flavour precursors to developing younger scales.     

Perinatal flavour learning and adaptation to being weaned: all the pig needs is smell

Perinatal flavour learning through the maternal diet is known to enhance flavour preference and acceptance of flavoured food in many species, yet still little is known about the mechanism underlying perinatal flavour learning. Previously we found positive effects of perinatal flavour learning on food intake, growth and behaviour of piglets postweaning, but no increased preference for the flavour. This suggests that flavour learning in pigs works through a reduction of weaning stress by the presence of the familiar flavour instead. The aim of this study was to investigate whether perinatal flavour learning reduces stress at weaning, and whether the effect is stronger when the familiar flavour is present in the food. Sows were offered an anethol-flavoured diet (Flavour treatment) or control diet (Control treatment) during late gestation and lactation. Flavour and Control piglets were provided with anethol either in their food (Food treatment) or in the air (Air treatment) after weaning. Preweaning and postweaning treatments did not affect food intake, preference or growth in the first two weeks postweaning but flavour treatment reduced the latency to eat (24 versus 35 hours, P = 0.02) and within-pen variation in growth (SD within-pen: 0.7 versus 1.2 kg, P<0.001). Salivary cortisol levels tended to be lower four and seven hours postweaning for Flavour piglets compared to Control piglets (4 hours: 2.5 versus 3.0 ng/ml, P = 0.05, 7 hours: 3.1 versus 3.4 ng/ml, P = 0.08). Flavour piglets played more and showed less damaging behaviours than Control piglets, indicating that the familiar flavour reduced stress around weaning. Few interaction effects were found between preweaning and postweaning treatment, and no effects of postweaning treatment. We conclude that in the newly weaned pig, perinatal flavour learning results in a reduction of stress when the familiar flavour is present, regardless of providing the flavour in the food or in the air.     

Shoot differentiation from protocorm callus cultures of <Emphasis Type="Italic">Vanilla planifolia</Emphasis> (Orchidaceae): proteomic and metabolic responses at early stage

Background  

Vanilla planifolia is an important Orchid commercially cultivated for the production of natural vanilla flavour. Vanilla plants are conventionally propagated by stem cuttings and thus causing injury to the mother plants. Regeneration and in vitro mass multiplication are proposed as an alternative to minimize damage to mother plants. Because mass production of V. planifolia through indirect shoot differentiation from callus culture is rare and may be a successful use of in vitro techniques for producing somaclonal variants, we have established a novel protocol for the regeneration of vanilla plants and investigated the initial biochemical and molecular mechanisms that trigger shoot organogenesis from embryogenic/organogenic callus.     

也门与中国产香丝草挥发油的化学成分分析和比较

目的：分析也门与中国产香丝草挥发油的化学成分,比较两者差异。方法：采用水蒸气蒸馏法提取也门及中国产香丝草的挥发油,运用气相色谱-质谱联用法（GC—MS）对挥发油进行组分分析,将两者的成分差异进行了比较。结果：从也门产香丝草挥发油中鉴定了34个成分,相对含量最多的分别为醇类（47．77％）、烯类（29．15％）、酯类（9．64％）,主要为雪松烯醇（18．54％）和环氧化香橙烯（18．75％）;从中国产香丝草挥发油中鉴定了56个成分,以酯类（31．20％）、烯类（28．05％）、醇类（14-29％）等挥发性物质为主,包括异戊酸香叶酯（18．81％）、反式--佛手柑油烯（10．31％）。结论：也门与中国产香丝草挥发油的组成具有较大的差异,是两者香味迥异的物质基础,也是也门产香丝草制作香料、美食的科学依据;     

The effect of viscosity on the perception of flavour

A trained sensory panel assessed flavour and sweetness intensity in solutions containing varying concentrations of hydroxy propyl methylcellulose (HPMC), sugar and flavour volatile. The flavour and sweetness of the viscous solutions were rated using magnitude estimation with a controlled modulus. In addition, the concentration of volatile released on the breath was measured using MS Nose. For low concentrations of HPMC (<0.5 g/100 g), perceived flavour intensity remained the same; however, a steady decrease was noted at higher concentrations (>0.6 g/100 g). The change in perceived intensity occurred at the point of random coil overlap (c(*)) for this hydrocolloid. The perceived sweetness of the solution showed a similar pattern with increasing HPMC concentration, although the inflection at c(*) was not so obvious. Despite the change in perceived flavour intensity, the actual concentration of volatile measured on the breath was not affected by the change in HPMC concentration. Low-order polynomial models were produced to describe perceived flavour intensity and sweetness in viscous solutions containing HPMC and potential explanations for the changes in perception are discussed.     

A mass spectrometric method for measuring flavour concentration/time profiles in human breath

Psychophysical work on flavour perception led to the developmentof a mass spectrometric method to monitor continuously the releaseof flavour components at the nose, breath-by-breath. The keyfeature of the measuring set-up is a special membrane interfacingwith a mass spectrometer. The method enables establishment ofthe effect of the matrix (oil or water) on flavour release rateand retention, and assignation of quantitative parameters. Amathematical model to evaluate the experimental curves was alsodeveloped.     

Nematicidal potential of Brassicaceae

Brassicaceae Burnett (syn. Cruciferae A. L. de Jussieu) include many important economic plants used as edibile or ornamental. They are commonly known as the “mustard” plant family due to the sharp, potent flavour of their main metabolites, the glucosinolates (GLSs) which contain sulfur. Glucosinolates coexist in vivo with glycosylated thioglucosidases, myrosinase(s), responsible of their hydrolysis with the production of bioactive cognate isothiocyanates (ITC). GLSs and ITCs function as defence bioactive metabolites against plant pathogens, insects and herbivores. The present review paper focus on GLSs role as bionematicides. The current knowledge on the efficacy of these phytochemicals against the most common phytoparasitic nematodes affecting crops of agriculture importance such as tomato, potato and grapevine is reported. Data from our ongoing research on the in vitro biocidal activity of glucosinolate extracts, and their main components, against the virus-vector nematode Xiphinema index Thorne & Allen and the carrot cyst nematode Heterodera carotae Jones are also described.     

Formation of flavour compounds in the Maillard reaction

This paper discusses the importance of the Maillard reaction for food quality and focuses on flavour compound formation. The most important classes of Maillard flavour compounds are indicated and it is shown where they are formed in the Maillard reaction. Some emphasis is given on the kinetics of formation of flavour compounds. It is concluded that the essential elements for predicting the formation of flavour compounds in the Maillard reaction are now established but much more work needs to be done on specific effects such as the amino acid type, the pH, water content and interactions in the food matrix. It is also concluded that most work is done on free amino acids but hardly anything on peptides and proteins, which could generate peptide- or protein-specific flavour compounds.     

Release cells, breath analysis and in-mouth analysis in flavour research

The flavour of a food or beverage is not perceived in a single event, but rather as a series of events experienced as the food is consumed. Recent methods in flavour research have taken account of this, and techniques have been developed to study flavour release in model systems (release cells or simulated mouths) and from the mouth or nose of assessors, while consuming foods. However, while there is agreement on the need in some cases for hydration or artificial saliva in simulated mouths, other parameters must be optimised on a case-by-case basis. Individual variability may still be a problem in breath analysis, and further work is required to determine the extent to which there are real differences in volatile profiles. The techniques of release cells and breath analysis must now be applied to provide data, which will allow flavour release to be modelled.     

Utilisation of the MVA pathway to produce elevated levels of the sesquiterpene α-copaene in potato tubers

Potato flavour is a complex trait resulting from the presence of a combination of volatile and non-volatile compounds. The aim of this work was to investigate the effect of specifically altering the volatile content of tubers and assess its impact on flavour. Tuber-specific over-expression of a potato α-copaene synthase gene resulted in enhanced levels (up to 15-fold higher than controls) of the sesquiterpene α-copaene. A positive correlation (R² = 0.8) between transgene expression level and α-copaene abundance was observed. No significant changes in the levels of volatiles other than α-copaene were detected. Non-volatile flavour compounds (sugars, glycoalkaloids, major umami amino acids and 5′-ribonucleotides) were also determined. Relationships between flavour compounds and sensory evaluation data were investigated. Evaluators could not detect any aroma differences in the transgenic samples compared with controls and no significant differences in taste attributes were found. Thus although successful engineering of potato tubers to accumulate high levels of the flavour volatile α-copaene was achieved, sensory analysis suggests that α-copaene is not a major component of potato flavour.     

Sheep deficient in vitamin E preferentially select for a feed with a higher concentration of vitamin E

Given the capacity of ruminants to modify diet selection based on metabolic needs, we hypothesised that, when given a choice, lambs experiencing a vitamin E deficiency would consume more of a vitamin E-enriched feed than lambs not deficient in vitamin E. Fifty-six Dohne Merino lambs were divided into two groups and fed either a vitamin E-deficient diet over 40 days to induce low plasma vitamin E or a vitamin E-enriched diet to induce high plasma vitamin E. The lambs were then offered a choice of vitamin E-enriched and vitamin E-deficient pellets. For half of the animals, the enriched diet was paired with strawberry flavour and the deficient diet was paired with orange flavour, while the reverse pairings were offered to the others. Lamb preference for the diets was measured daily for the following 15 days. There was a three-way interaction between the high and low vitamin E treatment groups×vitamin E content and type of flavour in the feed×time (days). The lambs preferred pellets flavoured with strawberry but this preference changed to orange flavour in vitamin E-deficient lambs if the orange flavour was paired with high vitamin E. Lambs without a deficiency continued to prefer strawberry-flavoured pellets, regardless of the vitamin E concentrations in the pellets. It is possible that self-learning contributed to the low vitamin E group of lambs changing preference to orange flavour in order to consume more vitamin E, presumably to remediate the deficiency.