title: Quantification of Nitro-toxins in Karaka (Corynocarpus laevigatus) Drupes

authors: MacAskill, Jessica Jane

abstract: The karaka (Corynocarpus laevigatus) is a tree native to New Zealand (NZ), found throughout the North and South Islands. Traditionally, many parts of the karaka were used by Māori, however the parts of the karaka of most interest are the berry and nut as they were valuable food sources, in particular the nut. Karaka was known to be a toxin-bearing food, however implementation of a traditional baking and soaking process meant that the nuts were left in states fit for consumption, more often than not. The nuts also had the benefit of being able to be stored for future use when other food sources were short in supply. Karaka was readily consumed up until the 1950s, after this consumption rates decreased rapidly, after the toxic effects were associated with the incorrect preparation of the nuts.

Studies on karaka have revealed that the toxicity of the nuts primarily arises from various nitropropanoyl glucopyranoses (NPGs), twelve of which have been detected in karaka. The quantity of these NPGs has been infrequently studied and it is often only one of the NPGs-karakin which is quantified, although it is believed the toxicity in nuts arises collectively from all of the NPGs. As a result, there is the need to be able to quantify the NPGs in karaka and look at potential toxin removal techniques. If toxin removal can be accomplished, there is the potential for karaka to be a marketable ‘traditional’ or ‘Kiwi’ food item. Additionally, the toxins removed as a by-product may prove to have their own potential commercial applications, for example as insecticides or repellents. 

Since all the NPGs are assumed to be toxic, a method was developed to quantify the total toxicity in the nuts. The method involves the release of NPA via acid hydrolysis of the nitropropanoyl ester groups of the NPGs. The NPA is then able to be measured and subsequently quantified using HPLC. The method incorporates a correction factor (CF) that was determined to give the original NPA content at a time of zero (NPA0), accounting for the unavoidable loss of NPA that arises from the hydrolysis method.

The average quantity of NPA in karaka nuts was found to range from 50.25 to 138.62 g kg-1 (dry weight) which is equivalent to 5.0 to 13.9%. These are much higher percentages than any previously reported because the method used in this study measured total NPA. Earlier methods measured a limited range of NPGs (often a single NPG) unhydrolysed and could have missed NPA arising from other compounds that contribute to total toxicity. Additionally, the concentrations of NPA in karaka nuts were influenced by a number of factors including intra and inter tree variation, storage conditions and ripeness. Although quantification was focused on determining NPA content in nuts, a test conducted also showed NPA to be present in increasingly lower levels in the berry flesh, shell and pellicle respectively. 

Nuts were subjected to various potential industrial processing techniques, treatment times and conditions, in order to determine their efficacy for toxin removal. Treatments included boiling, microwave cooking, soxhlet extraction, oven roasting, autoclaving and cold-water treatments. The efficiency of each treatment varied considerably, with both heat and water proving to be beneficial in toxin removal. However, treatments involving water were found to be more effective than heat treatments alone. Out of all treatment types, times and conditions tested, none were found to leave nuts with a NPA concentration lower than the estimated safe level of daily consumption for a 70 kg adult (< 1.75 mg). Additionally, only some of the treatments resulted in nuts being left in visually appealing states. At present, toxin removal by a single process in order to render karaka nuts safe to consume appears to be an impractical activity. However, if treatment protocols were combined and modified, there is the potential for the development of an effective detoxification process. Furthermore, tests on the treatment solutions revealed that NPA can be obtained in solution as a by-product of nut treatment; with cold-water proving to be more effective than treatments that also used heat. Obtaining NPA as a by-product of toxin removal in nuts appears to be a feasible option for a natural source of NPA.

text: Quantification of Nitro-toxins in Karaka (Corynocarpus laevigatus) Drupes The karaka (Corynocarpus laevigatus) is a tree native to New Zealand (NZ), found throughout the North and South Islands. Traditionally, many parts of the karaka were used by Māori, however the parts of the karaka of most interest are the berry and nut as they were valuable food sources, in particular the nut. Karaka was known to be a toxin-bearing food, however implementation of a traditional baking and soaking process meant that the nuts were left in states fit for consumption, more often than not. The nuts also had the benefit of being able to be stored for future use when other food sources were short in supply. Karaka was readily consumed up until the 1950s, after this consumption rates decreased rapidly, after the toxic effects were associated with the incorrect preparation of the nuts.

Studies on karaka have revealed that the toxicity of the nuts primarily arises from various nitropropanoyl glucopyranoses (NPGs), twelve of which have been detected in karaka. The quantity of these NPGs has been infrequently studied and it is often only one of the NPGs-karakin which is quantified, although it is believed the toxicity in nuts arises collectively from all of the NPGs. As a result, there is the need to be able to quantify the NPGs in karaka and look at potential toxin removal techniques. If toxin removal can be accomplished, there is the potential for karaka to be a marketable ‘traditional’ or ‘Kiwi’ food item. Additionally, the toxins removed as a by-product may prove to have their own potential commercial applications, for example as insecticides or repellents. 

Since all the NPGs are assumed to be toxic, a method was developed to quantify the total toxicity in the nuts. The method involves the release of NPA via acid hydrolysis of the nitropropanoyl ester groups of the NPGs. The NPA is then able to be measured and subsequently quantified using HPLC. The method incorporates a correction factor (CF) that was determined to give the original NPA content at a time of zero (NPA0), accounting for the unavoidable loss of NPA that arises from the hydrolysis method.

The average quantity of NPA in karaka nuts was found to range from 50.25 to 138.62 g kg-1 (dry weight) which is equivalent to 5.0 to 13.9%. These are much higher percentages than any previously reported because the method used in this study measured total NPA. Earlier methods measured a limited range of NPGs (often a single NPG) unhydrolysed and could have missed NPA arising from other compounds that contribute to total toxicity. Additionally, the concentrations of NPA in karaka nuts were influenced by a number of factors including intra and inter tree variation, storage conditions and ripeness. Although quantification was focused on determining NPA content in nuts, a test conducted also showed NPA to be present in increasingly lower levels in the berry flesh, shell and pellicle respectively. 

Nuts were subjected to various potential industrial processing techniques, treatment times and conditions, in order to determine their efficacy for toxin removal. Treatments included boiling, microwave cooking, soxhlet extraction, oven roasting, autoclaving and cold-water treatments. The efficiency of each treatment varied considerably, with both heat and water proving to be beneficial in toxin removal. However, treatments involving water were found to be more effective than heat treatments alone. Out of all treatment types, times and conditions tested, none were found to leave nuts with a NPA concentration lower than the estimated safe level of daily consumption for a 70 kg adult (< 1.75 mg). Additionally, only some of the treatments resulted in nuts being left in visually appealing states. At present, toxin removal by a single process in order to render karaka nuts safe to consume appears to be an impractical activity. However, if treatment protocols were combined and modified, there is the potential for the development of an effective detoxification process. Furthermore, tests on the treatment solutions revealed that NPA can be obtained in solution as a by-product of nut treatment; with cold-water proving to be more effective than treatments that also used heat. Obtaining NPA as a by-product of toxin removal in nuts appears to be a feasible option for a natural source of NPA.

year: 2013

title: Home and the spirit in the Maori world

authors: Nikora, Linda Waimarie

abstract: Today we explore home as a place of spiritual belonging and continuity and how tangi relies on the genealogical connectedness of ancestral and living communities to care for the tūpāpaku, the human remains, and wairua, the spirit of the deceased, as well as the living. While colonisation and westernisation have changed us, the institution of tangi, our rituals of death and mourning, have remained since pre-encounter times. In the face of death, tangi and its repetitive ritualised pattern of encounter and mourning might be viewed as a lifeline to hold on to as the disturbance and turmoil spawned by death is endured.

We begin this paper by returning to the beginning, the place of potentiality to contemplate our spiritual origins and life endowments. We consider the nature of Māori beliefs about a spiritual afterlife and how through the institution of tangi we guide and support the departing spirit on its way. We argue that these rituals of departure and support are most optimally performed within the context of our marae and spiritual landscapes. Reinforcing this, the interment of the deceased amongst kin enhances our togetherness, in life and death, and protects us from entities with malevolent intent. For these reasons, we reaffirm the rightness of our beliefs and practices. Contestation of tūpāpaku, an act of spiritual responsibility in which tūpāpaku are returned to their tribal homelands for mourning and interment amongst kin is presented as an exemplar of right spiritual practice. We conclude with a discussion of some challenges Māori must confront to live life more consciously in spiritually responsible ways and in continuity with our origins and futures.

text: Home and the spirit in the Maori world Today we explore home as a place of spiritual belonging and continuity and how tangi relies on the genealogical connectedness of ancestral and living communities to care for the tūpāpaku, the human remains, and wairua, the spirit of the deceased, as well as the living. While colonisation and westernisation have changed us, the institution of tangi, our rituals of death and mourning, have remained since pre-encounter times. In the face of death, tangi and its repetitive ritualised pattern of encounter and mourning might be viewed as a lifeline to hold on to as the disturbance and turmoil spawned by death is endured.

We begin this paper by returning to the beginning, the place of potentiality to contemplate our spiritual origins and life endowments. We consider the nature of Māori beliefs about a spiritual afterlife and how through the institution of tangi we guide and support the departing spirit on its way. We argue that these rituals of departure and support are most optimally performed within the context of our marae and spiritual landscapes. Reinforcing this, the interment of the deceased amongst kin enhances our togetherness, in life and death, and protects us from entities with malevolent intent. For these reasons, we reaffirm the rightness of our beliefs and practices. Contestation of tūpāpaku, an act of spiritual responsibility in which tūpāpaku are returned to their tribal homelands for mourning and interment amongst kin is presented as an exemplar of right spiritual practice. We conclude with a discussion of some challenges Māori must confront to live life more consciously in spiritually responsible ways and in continuity with our origins and futures.

year: 2013

title: Effects of raised safety platforms (RSPs) on travel time and traffic delay at roundabouts

authors: Singh, Dharmendra

subjects: Raised Safety Platform

abstract: Raised safety platforms (RSPs) are vertical deflection devices that utilise vertical acceleration to slow vehicle operating speeds down to safe systems-compliant speeds. These devices are not as jarring for drivers as a traditional judder bar and are specifically designed for motorist comfort when traveling at a safe and appropriate speed. RSPs have been specifically identified through the Austroads Guide to Traffic Management and New Zealand Transport Agency (NZTA) Standard Safety Intervention Toolkit as a key safe systems safety intervention.

RSPs are also part of best practice guidance and are designed to slow vehicle speeds enough so that when people make mistakes, they have time to react and avoid a crash. If a crash were still to happen it is kinetic impact energy which determines the severity outcome of a crash is lower. At lower speeds the likelihood of a death or serious injury occurring as a result is drastically reduced.

Safe Systems is a road safety philosophy that requires industry practitioners to provide a more forgiving road system reducing the harm to the human body in the event of a crash. Safe systems have four key pillars safe roads and roadside, safe speeds, safe vehicles, and safe road users. Safe speeds are the areas within which RSPs sit.

Although there are proven safety benefits of RSPs through various literature sources there is still a common user perception that these devices cause a decrease in operational efficiency. Literature is also light on this topic and in cases where past literature is available, they seem to contradict with each other. Some user arguments are that RSPs create congestion at intersections resulting in an increased travel time.

The aim of this thesis report was to provide data-based clarity on the effects of the RSP on travel time and traffic delay at roundabouts to help clarify this area of knowledge gap. This report also seeks to understand effects on traffic speed, crashes, queue lengths, and LOS at roundabouts as a result of RSPs.

This report specifically focuses on roundabouts due to a lack of roundabout-related operational literature as the majority of RSP applications have been at signalised intersections. It should be noted that RSPs are still a new and emerging idea for Australia and New Zealand (NZ). RSPs are a widely used safety intervention in European countries such as the Netherlands.

Investigation in this paper has been done through a review of the literature and quantitative assessment of a sample of sites through microsimulation traffic modeling using Multimodal Traffic Simulation Software. Based on the findings of this paper it is identified that there is a negligible change in traffic delay and a decrease in travel time as a result of RSPs at roundabouts.

The findings of this research shows that RSPs create smoother traffic flow, and safer and better gap selection for vehicles entering a roundabout resulting in improved or the same efficiency for the intersection when compared to pre RSP operation. Some increases in queue lengths was evident on the approach to RSPs and this could relate to driver perception of an increase in congestion. There is no evidence from this paper that supports this as the overall LOS remains unchanged or is improved.

This paper also found that speeds dropped notably on approach to RSPs which resulted in a change in driver psychology where drivers were yielding more at the slower speed. Crash data also showed a decreasing trend in the number of crashes and their severity following RSP installation across all the sites studied. These finding also support past literature on RSP speed and crash reductions.

text: Effects of raised safety platforms (RSPs) on travel time and traffic delay at roundabouts Raised safety platforms (RSPs) are vertical deflection devices that utilise vertical acceleration to slow vehicle operating speeds down to safe systems-compliant speeds. These devices are not as jarring for drivers as a traditional judder bar and are specifically designed for motorist comfort when traveling at a safe and appropriate speed. RSPs have been specifically identified through the Austroads Guide to Traffic Management and New Zealand Transport Agency (NZTA) Standard Safety Intervention Toolkit as a key safe systems safety intervention.

RSPs are also part of best practice guidance and are designed to slow vehicle speeds enough so that when people make mistakes, they have time to react and avoid a crash. If a crash were still to happen it is kinetic impact energy which determines the severity outcome of a crash is lower. At lower speeds the likelihood of a death or serious injury occurring as a result is drastically reduced.

Safe Systems is a road safety philosophy that requires industry practitioners to provide a more forgiving road system reducing the harm to the human body in the event of a crash. Safe systems have four key pillars safe roads and roadside, safe speeds, safe vehicles, and safe road users. Safe speeds are the areas within which RSPs sit.

Although there are proven safety benefits of RSPs through various literature sources there is still a common user perception that these devices cause a decrease in operational efficiency. Literature is also light on this topic and in cases where past literature is available, they seem to contradict with each other. Some user arguments are that RSPs create congestion at intersections resulting in an increased travel time.

The aim of this thesis report was to provide data-based clarity on the effects of the RSP on travel time and traffic delay at roundabouts to help clarify this area of knowledge gap. This report also seeks to understand effects on traffic speed, crashes, queue lengths, and LOS at roundabouts as a result of RSPs.

This report specifically focuses on roundabouts due to a lack of roundabout-related operational literature as the majority of RSP applications have been at signalised intersections. It should be noted that RSPs are still a new and emerging idea for Australia and New Zealand (NZ). RSPs are a widely used safety intervention in European countries such as the Netherlands.

Investigation in this paper has been done through a review of the literature and quantitative assessment of a sample of sites through microsimulation traffic modeling using Multimodal Traffic Simulation Software. Based on the findings of this paper it is identified that there is a negligible change in traffic delay and a decrease in travel time as a result of RSPs at roundabouts.

The findings of this research shows that RSPs create smoother traffic flow, and safer and better gap selection for vehicles entering a roundabout resulting in improved or the same efficiency for the intersection when compared to pre RSP operation. Some increases in queue lengths was evident on the approach to RSPs and this could relate to driver perception of an increase in congestion. There is no evidence from this paper that supports this as the overall LOS remains unchanged or is improved.

This paper also found that speeds dropped notably on approach to RSPs which resulted in a change in driver psychology where drivers were yielding more at the slower speed. Crash data also showed a decreasing trend in the number of crashes and their severity following RSP installation across all the sites studied. These finding also support past literature on RSP speed and crash reductions.

year: 2024