Immobilized enzyme technology for debittering citrus fruit juices

There has been increased interest in the use of immobilized enzymes in fruit juice industry for debittering of citrus fruit juices due to their high efficiency to remove bitter flavonoids. The structure of naringin, responsible for immediate bitterness, and of limonin, responsible for "delayed bitterness" has been discussed. This chapter also discusses various attempts that have been made to immobilize enzymes on an appropriate support so as to enable their use in debittering of citrus fruit juices. These include physicochemical and enzyme biotechnological approaches which makes the fruit juice more acceptable and cost effective to the consumer. Despite of high volume of production of citrus fruits and fruit juices, suitable processes to produce non-bitter citrus juice by immobilized enzymes technology has not yet commercialized globally.

Molecular characterization and enzymatic hydrolysis of flavanoid extracted from citrus waste

The citrus fruit processing industry generates substantial quantities of waste rich in phenolic substances, which is a valuable natural source of polyphenols (flavonoids) such as naringin and its disposal is becoming a major problem. In the US alone, the juice processing of oranges and grapefruit generates over 5 Mt of citrus waste every year. In the case of India, about 2.15 Mt of citrus peel out of 6.28 Mt of citrus fruits are produced yearly from citrus juice processing. In case of Australia, about 15-40% of citrus peel waste is generated by processing of citrus fruit (0.85 Mt). Thus Isolation of functional compounds (mostly flavanoids) and their further processing can be of interest to the food and pharmaceutical industry. This peel is rich in naringin and may be used for rhamnose production by utilizing α-L-rhamnosidase (EC 3.2.1.40), an enzyme that catalyzes the cleavage of terminal rhamnosyl groups from naringin to yield prunin and rhamnose. We recently purified recombinant α-L-rhamnosidase from E. coli cells using immobilized metal-chelate affinity chromatography (IMAC) and used it for naringin hydrolysis. The purified enzyme established hydrolysis of naringin extracted from citrus peel and thus endorses its industrial applicability for producing rhamnose. Infrared (IR) spectroscopy confirmed molecular characteristics of naringin extracted from citrus peel waste.

Which food-related behaviours are associated with healthier intakes of fruits and vegetables among women?

Objective To examine associations between shopping, food preparation, meal and eating behaviours and fruit and vegetable intake among women.
Design Cross-sectional survey.
Setting Community-based sample from metropolitan Melbourne, Australia.
Subjects A sample of 1136 women aged 18–65 years, randomly selected from the electoral roll.
Results Food-related behaviours reflecting organisation and forward-planning, as well as enjoyment of and high perceived value of meal shopping, preparation and consumption were associated with healthier intakes of fruits and vegetables. For example, women who more frequently planned meals before they went shopping, wrote a shopping list, enjoyed food shopping, planned in the morning what they will eat for dinner that night, planned what they will eat for lunch, reported they enjoy cooking, liked trying new recipes and who reported they sometimes prepare dishes ahead of time were more likely to consume two or more servings of vegetables daily. Conversely, women who frequently found cooking a chore, spent less than 15 minutes preparing dinner, decided on the night what they will eat for dinner, ate in a fast-food restaurant, ate takeaway meals from a fast-food restaurant, ate dinner and snacks while watching television and who frequently ate on the run were less likely to eat two or more servings of vegetables daily.
Conclusions Practical strategies based on these behavioural characteristics could be trialled in interventions aimed at promoting fruit and vegetable consumption among women.

Fruits of the vine : reflection on performance-making through blogs

In 2006 Drama Australian launched the VINE Project, bringing together groups of drama students within schools, universities and the broader community to make group performances based on a common theme. Using the VINE Project's multi-user blogging environment, group or individuals maintained blogs of their performance-making processes. This allowed the work to be shared within the VINE Project community and potentially a world-wide audience.

This paper contributes to the discussion on the applications of information and communication technologies (ICT) in drama and theatre education. It considers the blog, emerging from web-culture, as a space for groups and individuals to reflect upon performance-making processes. A range of VINE Project participants was asked to reflect and comment upon the performance-making and blogging experience. This paper presents emerging understandings of the role of blogs in encouraging reflection, in creating a sense of group identity and significance, in validating performance-making processes and in building a sense of connection and community among student performance-makers.

Citrus peel influences the production of an extracellular naringinase by Staphylococcus xylosus MAK2 in a stirred tank reactor

Staphylococcus xylosus MAK2, Gram-positive coccus, a nonpathogenic member of the coagulase-negative Staphylococcus family was isolated from soil and used to produce naringinase in a stirred tank reactor. An initial medium at pH 5.5 and a cultivation temperature of 30°C was found to be optimal for enzyme production. The addition of Ca⁺² caused stimulation of enzyme activity. The effect of various physico-chemical parameters, such as pH, temperature, agitation, and inducer concentration was studied. The enzyme production was enhanced by the addition of citrus peel powder (CPP) in the optimized medium. A twofold increase in naringinase production was achieved using different technological combinations. The process optimization using technological combinations allowed rapid optimization of large number of variables, which significantly improved enzyme production in a 5-l reactor in 34 h. An increase in sugar concentration (15 gl^-1) in the fermentation medium further increased naringinase production (8.9 IUml^-1) in the bioreactor. Thus, availability of naringinase renders it attractive for potential biotechnological applications in citrus processing industry.

Hydrolysis of citrus peel waste with recombinant rhamnosidase for bioenergy generation

Large amounts of Citrus peel (rich in poly-phenolic compounds) are generated as a by-product of the juice processing industry. Development of alternative, higher valued products utilizing peel waste from grapefruit, oranges, Valencia and other citrus fruit would benefit citrus juice processors by providing them with means to profitably process their peel waste and to avoid environmentally hazardous dumping. Citrus peel waste [CPW, comprised of peel, membranes and juice vesicles] contains a high level of polyphenols and has been used for the production of animal feed, single-cell protein, fibre, enzyme(s), immobilization support & bio-sorbent for heavy metal removal. Naringin (a major tri-hydroxy flavonoid glycoside) is available in large amounts in citrus peel, processed juice and can be extracted from citrus peel waste1. The extracted naringin is further hydrolysed by rhamnosidase to produce D-rhamnose for the production of ethanol and other fermentation products. We have produced a recombinant enzyme2 that has the ability to catalyse the cleavage of terminal rhamnoside groups from naringin to prunin and rhamnose. We have recovered important sugar “D-rhamnose” from the processed waste which would be utilized for ethanol production3. This presentation will summarize current efforts to develop an enzymatic treatment which would facilitate the economical processing of citrus waste for bioenergy generation.

Breastfeeding mothers consume more vegetables and a greater variety of fruits and vegetables than non-breastfeeding peers : the influence of socioeconomic position

Aim:  This study compared the diets of breastfeeding and non-breastfeeding mothers from socioeconomically diverse regions of Melbourne to determine whether breastfeeding is a marker for healthier maternal dietary intakes.

Methods:  This cross-sectional study obtained information via self-reported questionnaire from 529 first-time Melbourne mothers. Breastfeeding status was determined when the children were 3.9 months. Diet information was obtained using a validated Food Frequency Questionnaire. Maternal diet was assessed by seven indicators: average daily intake of fruit, vegetables, non-core drinks, non-core sweet snacks, non-core savoury snacks, variety of fruit and variety of vegetables eaten in the preceding 12 months. Associations between breastfeeding status and each dietary variable were assessed using linear regression analyses. Socioeconomic position, maternal body mass index and the cluster-based sampling design were controlled for.

Results:  Of the 529 subjects, 70% were breastfeeding their child. Compared with non-breastfeeding mothers, breastfeeding mothers were found to consume more serves of vegetables (P= 0.001), a greater variety of fruit and vegetables (P= 0.001 and P≤ 0.001 respectively), and sweet snacks were consumed more frequently (P= 0.006). Differences were observed between low and high socioeconomic position mothers for fruit serves (P= 0.003), vegetable serves (P= 0.010) and fruit variety (P= 0.006). These associations persisted after controlling for socioeconomic position and maternal body mass index.

Conclusions:  The association between infant feeding (breastfeeding) and some aspects of maternal diet provides further evidence suggesting a link between maternal and child diets from a younger age than previously examined.

Effects of trunk-shaker harvester and ethephon on plant water status, leaf gas exchange, and yield of citrus cultivated under Mediterranean conditions

This work was aimed to study whether the application of ethephon as an abscission agent and mechanical harvest using a trunk shaker have any effect on plant water status, leaf gas exchange, and yield of mandarin and orange trees cultivated under Mediterranean conditions. The experiment was performed from 2008 to 2011 in five commercial orchards where parameters related to the plant water status and leaf gas exchange were measured before the application of ethephon, at harvest time and at different occasions after harvest. In addition, the effects of ethephon dose on yield in the current and subsequent seasons were also evaluated. Results showed that ethephon applications and mechanical harvest did not detrimentally affect plant water status in any of the cultivars studied. Furthermore, either had no effect or had a short temporal decrease effect on leaf gas exchange depending on the cultivar studied although with no consequences for the fruit yield obtained during the current season. Increasing ethephon doses led to fruit yield reductions in the mandarin ‘Orogrande’ trees in subsequent seasons. When trunk-shaker and ethephon applications were combined, however, yields from the late-maturing orange significantly decline in subsequent seasons. Overall, results show that using a trunk shaker is a viable technique to mechanically harvest citrus trees destined to both fresh and industry market and can be considered as an alternative to the traditional manual harvest usually performed under Mediterranean conditions. However, its use cannot be recommended for late-maturing oranges, such as the ‘Navel Lane Late’ in which mature fruit and fruitlets coexist in the tree at the time of harvest.