729 research outputs found
Development of gluten-free wrap bread : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Food Technology, Massey University, Albany, New Zealand
Gluten, the storage protein in wheat, barley and rye is associated with coeliac disease,
wheat allergy and non-coeliac gluten sensitivity. The clinical symptoms include diarrhoea,
anaemia, nausea, mouth sore and psychological symptoms and in some cases a gluten free
diet may reduce the severity of irritable bowel disease (IBD). Gluten-related disorders can be
prevented by the omission of gluten from the diet. Currently, there is an increasing demand
for gluten-free foods due to consumer awareness of gluten-related disorders as well as people
seeking to reduce possible dietary risks. New Zealand’s market for gluten-free foods is
presently estimated at nearly four million US dollars.
The development and production of gluten-free bread presents major technological
challenges due to the role of gluten in developing the characteristic structure of both the raw
dough and subsequent loaf texture. The main ingredients of bread are water and cereal flours
which provide the primary structure to the baked product. Wheat grain is a traditional and
common cereal that is milled into bread flour. When wheat flour is hydrated with water,
gluten, the protein component hydrates to become a continuous cohesive viscoelastic network
entrapping starch granules. This highly elastic network retains CO2 gas produced by yeast
and sugar during leavening, thus forming the foam structure of bread. Gluten replacements
that mimic the viscoelastic properties of gluten have been widely investigated for gluten free
baked products including flatbread. Flatbread is popular for use in ready-to-eat convenient
foods due to its large crust to crumb ratio. Wrap bread is a typical flatbread that can be rolled
to hold various fillings. The manufacture of gluten-free wrap breads mainly suffers from poor
rollability which is an essential property of the product. Thus, the present study investigated
the development of gluten-free wrap bread (GFW) using xanthan gum, guar gum,
carboxmethyl cellulose (CMC) as possible replacers for gluten, coconut oil was also added to
improve flexibility of the bread. The formulations were investigated and optimised in four
integrated phases.
In phase 1, guar and xanthan gums were studied as possible gluten replacers during the
development of GFWs. GFW samples (n = 16) made from four formulations under four
baking conditions (200°C/2 min, 200°C/4 min, 220°C/2 min, 220°C/4 min) were analysed for
baking weight loss and rollability. Baking weight loss was determined as moisture loss during
baking, while rollability was measured as the ability of the freshly cooked bread to conform
to shape (1-5 scale) as it was rolled around a 3-cm diameter wooden dowel (rod). A mixture
of guar and xanthan gums (1:1) produced GFWs with better rollability and less baking weight
loss than either gum alone. GFW samples baked at the higher temperature for the longer time
generally had higher rollability. The highest average rollability score (3) obtained for this
phase was considered low for wrap breads developed in phase 2.
In phase 2, GFWs (n = 20) made from five formulations containing both xanthan and
guar gums (1:1), CMC, and coconut oil were baked at 230°C for 2 or 4 min or at 240°C for 2
or 4 min. Freshly baked GFWs were analysed for baking weight loss, water activity, and
colour. Rollability using 1 1-cm diameter dowel and visible mould growth of the GFWs were
determined during storage for 28 days (4°C). Products produced in phase 2 had no visible
mould growth during storage for 3 weeks (4°C). The inclusion of xanthan-guar gum, CMC
and coconut oil into GFWs baked at 240°C/2 min may have contributed to high rollability
and low baking weight loss. The effect of each test ingredient (xanthan-guar, CMC, and
coconut oil) on the properties of GFWs was the subject of phase 3.
In phase 3, a basic formulation made with three levels (9 formulations) each of coconut
oil, CMC and xanthan-gum gum were optimized using the Taguchi method to test the effect
of each ingredient in the basic formulation. GFWs made using the 9 formulations were
analysed by physical and sensory tests over three weeks storage at 4°C during which mould
growth was assessed visually. Products in phase 3 had no visible mould growth during
storage for three weeks (4°C). GFWs with high level of coconut oil (12%) were characterised
by high baking weight loss, high whiteness index and a shorter firmer texture (high rupture
force and low rupture distance). CMC (0.3%) and xanthan-guar gum (1%) may have
contributed to low water activity, high rollability, high rupture distance and high rupture
force during storage. Results indicated that 0.3% CMC and 1% xanthan-guar gum were the
optimum levels for these ingredients. As the optimized levels of coconut oil could not be
confirmed in this phase, three promising formulations with different levels of coconut oil (8,
10, 12%) were evaluated in phase 4.
In phase 4, three products were produced using 3 optimised formulations from phase 3
and were analysed by physical tests and sensory evaluation during storage for two weeks
(4°C). The 3 optimised formulations selected from phase 3 were: (1) base formulation plus 8%
coconut oil, 0.3% CMC and 1% xanthan-guar gum; (2) base formulation plus 10% coconut
oil, 0.3% CMC and 1% xanthan-guar gum; (3) base formulation plus 12% coconut oil, 0.3%
CMC and 1% xanthan-guar gum. Among the three formulations, samples containing 12%
coconut oil, 0.3% CMC and 1% xanthan-guar gum had the highest consumer sensory
acceptability and were characterised by high rollability, and a more flexible texture (moderate
rupture force and greater rupture distance) and low baking weight loss
Ordering-sensitive and Semantic-aware Topic Modeling
Topic modeling of textual corpora is an important and challenging problem. In
most previous work, the "bag-of-words" assumption is usually made which ignores
the ordering of words. This assumption simplifies the computation, but it
unrealistically loses the ordering information and the semantic of words in the
context. In this paper, we present a Gaussian Mixture Neural Topic Model
(GMNTM) which incorporates both the ordering of words and the semantic meaning
of sentences into topic modeling. Specifically, we represent each topic as a
cluster of multi-dimensional vectors and embed the corpus into a collection of
vectors generated by the Gaussian mixture model. Each word is affected not only
by its topic, but also by the embedding vector of its surrounding words and the
context. The Gaussian mixture components and the topic of documents, sentences
and words can be learnt jointly. Extensive experiments show that our model can
learn better topics and more accurate word distributions for each topic.
Quantitatively, comparing to state-of-the-art topic modeling approaches, GMNTM
obtains significantly better performance in terms of perplexity, retrieval
accuracy and classification accuracy.Comment: To appear in proceedings of AAAI 201
Multi-Frame Quality Enhancement for Compressed Video
The past few years have witnessed great success in applying deep learning to
enhance the quality of compressed image/video. The existing approaches mainly
focus on enhancing the quality of a single frame, ignoring the similarity
between consecutive frames. In this paper, we investigate that heavy quality
fluctuation exists across compressed video frames, and thus low quality frames
can be enhanced using the neighboring high quality frames, seen as Multi-Frame
Quality Enhancement (MFQE). Accordingly, this paper proposes an MFQE approach
for compressed video, as a first attempt in this direction. In our approach, we
firstly develop a Support Vector Machine (SVM) based detector to locate Peak
Quality Frames (PQFs) in compressed video. Then, a novel Multi-Frame
Convolutional Neural Network (MF-CNN) is designed to enhance the quality of
compressed video, in which the non-PQF and its nearest two PQFs are as the
input. The MF-CNN compensates motion between the non-PQF and PQFs through the
Motion Compensation subnet (MC-subnet). Subsequently, the Quality Enhancement
subnet (QE-subnet) reduces compression artifacts of the non-PQF with the help
of its nearest PQFs. Finally, the experiments validate the effectiveness and
generality of our MFQE approach in advancing the state-of-the-art quality
enhancement of compressed video. The code of our MFQE approach is available at
https://github.com/ryangBUAA/MFQE.gitComment: to appear in CVPR 201
Reconciling the Varied Stories
Arniko—the celebrated traveler, painter, architect, and sculptor—traveled to the court of the Yuan Empire in the 13th century, centuries before the modern states of Nepal and China came into existence. Arniko’s journey traverses boundaries and borders, including those of modern nation-states. However, modern myths invented and circulated between the 1940s to the 1980s prune and flatten this complexity into a framework based on European languages and norms to impose order and control over diverse local viewpoints and interpretations. Nepaliness is constructed by attributing ethnicity and citizenship to Arniko, and projected onto an ancient past, to impute a long-standing friendship between Nepal and China. We investigate the myths through a transcultural lens and show how a variety of actors use Arniko to fulfill their agendas of decolonization and nationalization and how these nuanced agendas have affected their construction of Arniko. Moreover, based on an analysis of art that is attributed to Arniko, we introduce methodology from art history to provide an alternative transcultural method for “reconstructing” Arniko. We argue that the modern myths about Arniko are constructed, maintained, and performed as ideological and territorialization processes of control over disputed geography and ethnic cultural identities
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