Green fodder feeding for enhancing conjugated linoleic acid

Beverage
Green fodder feeding for
enhancing conjugated linoleic acid
content of buffalo milk
Conjugated linoleic acid (CLA)
is an intermediary product produced
during the biohydrogenation of
polyunsaturated fatty acids in the rumen.
Concentrates and fodders are rich
sources of polyunsaturated fatty acids.
Foods of animal origin especially dairy
products are the major sources of CLA
for humans and are reputed to have therapeutic health values including anticarcinogenic properties. The scientists at Dairy Cattle Nutrition Division,
National Dairy Research Institute, Karnal, Haryana, India and Utah State
University, Logan, USA made attempt to increase CLA content in milk of
buffaloes by feeding them on Berseem (Trifolium alexandrinum Linn.)
fodder. Eighteen Murrah buffaloes (Bos bubalis), having similar milk yield
and stage of lactation were divided into three groups. All the groups were
offered ad lib wheat straw during the 60-day experimental period.
Their nutritional requirements were fulfilled through a concentrate mixture
(Group I), concentrate mixture + Berseem (Group II) and Berseem (Group
III). The ratio of Berseem, wheat straw and concentrate in the diet was
0:42:58, 50:25:25 and 87:13:0 on dry matter basis in the three groups,
respectively. Milk yield was recorded daily and its chemical composition
was determined fortnightly. Milk products such as ghee, paneer and
mozzarella cheese were prepared using the milk of each group at fortnightly
intervals. There was no effect of dietary treatments on milk yield and its
composition. Average total CLA content (mg/g fat) was 7.7, 13.4, 17.0 in
milk; 9.1, 13.4, 18.3 in paneer; 8.2, 12.7, 18.8 in ghee; and 8.0, 12.0
and 16.3 in cheese in Groups I-III, respectively, showing increase in CLA in
milk and milk products (P<0.1) due to Berseem feeding. The major fraction
of CLA was cis 9, trans 11 CLA (C18:2), which was highest in Group III
followed by Groups II and I. Omega-3 fatty acids content in milk fat was 4.5,
9.9 and 14.2 mg/g in Groups I-III, whereas the value for omega-6 in respective
groups was 16.4, 16.0 and 16.0 mg/g. Similar trends were observed in the
corresponding milk products. The values of omega-3 were higher (0.1) in
Group III but there was no change in omega-6 content due to the dietary
treatments. The ratio of omega-3 and omega-6 fatty acids in milk and milk
products was 1:1 in Group III, fed mainly on Berseem fodder [Tyagi AK,
Kewalramani N, Dhiman TR, Kaur H, Singhal KK and Kanwajia SK, Enhancement of the
conjugated linoleic acid content of buffalo milk and milk products through green fodder
feeding, Anim Feed Sci Technol, 2007, 133(3-4), 351-358].
458
Influence of
coffee/water ratio on
the final quality of
espresso coffee
Espresso coffee is a polyphasic beverage
in which the physico-chemical and sensory
characteristics obviously depend on both the
selection of ground roasted coffee and the
technical conditions of the percolation process.
The researchers at Food Science and Technology,
and Toxicology Department, School of Pharmacy,
University of Navarra, Pamplona, Spain evaluated
the influence of the coffee/water ratio on the
physico-chemical and sensory quality of espresso
coffee. Furthermore, the influence of botanical
varieties, viz. Coffea arabica Linn. var.
arabica and C. robusta Lind. var. robusta
and the type of roast (conventional and
torrefacto) on the selection of coffee/water ratio
was studied. During experiment some sensory
attributes, such as bitterness, astringency and
burnt, acrid and earthy/musty flavours were
proposed as relevant to the selection of 6.5g/40
ml or 7.5g/40ml in conventional roasted coffees
(arabica 100% and robusta blend), and 6.5g/
40ml in torrefacto roasted coffees. The addition
of sugar during the roasting process in torrefacto
roast coffees seemed to contribute to a higher
generation of acids, melanoidins and other
compounds by the Maillard reaction or
caramelisation, which helped in selecting the
lowest coffee/water ratio [Andueza Susana, Vila María
A, Peña M Paz de
and Cid Concepción,
Influence of coffee/
water ratio on the
final quality of
espresso coffee,
J Sci Food Agric,
2007,
87(4),
586-592].
Coffea arabica
Natural Product Radiance
Beverage
Pineapple juice and its fractions
inhibit enzymatic browning of banana
Many types of fruits, especially
bananas become brown rapidly when their
tissues are cut or bruised. The brown
colour is developed due to the enzymatic
oxidation of phenols to quinones by
polyphenol oxidase (PPO) in the presence
of oxygen. Enzymatic browning impairs
not only the colour of fresh fruits but also
the flavour and the nutritional quality.
Sulfites act as PPO inhibitors by
serving as reducing agents and also react
with intermediates to prevent pigment
formation but nowadays, consumers are
concerned about the possible dangers of
synthetic food additives. Pineapple
[Ananas comosus (Linn.) Merr.]
juice is a popular product due to its very
pleasant aroma and flavour. The
researchers of Department of Food Science
and Technology, Faculty of Agro-industry,
Kasetsart
University,
Bangkok and Department
of Food Science and
Technology, Oregon State
University, Corvallis,
Oregon identified the
fraction of pineapple juice
that was most effective for
banana PPO inhibition and
preventing enzymatic
browning in banana puree.
The results revealed that after storage of
banana slices at 15ºC for 3 days, pineapple
juice showed browning inhibition to a
similar extent as 8 mM ascorbic acid but
less than 4mM sodium metabisulfite.
Fractionation of pineapple juice by a solidphase C 18 cartridge revealed that the
directly eluted fraction (DE fraction)
inhibited banana polyphenol oxidase
(PPO) about 100% when
compared to the control. The
DE fraction also showed more
inhibitory effect than 8mM
ascorbic acid in enzymatic
browning inhibition of
banana puree during storage
at 5ºC for 24h. Further
identification of the DE
fraction by fractionation with
ion exchange chromatography
and confirmation using model systems
indicated that malic acid and citric acid
play an important role in the enzymatic
browning inhibition of banana PPO
[ Chaisakdanugull Chitsuda, Theerakulkait
Chockchai and Wrolstad Ronald E, Pineapple Juice
and Its Fractions in Enzymatic Browning Inhibition
of Banana [Musa (AAA Group) Gros Michel], J
Agric Food Chem, 2007, 55(10), 42524257].
Deodorization of off-odour during
sweet potato juice production
Although sweet potato has a great
potential as an ingredient in functional
foods, it exhibits a potential off-flavour
in the boiling process. The mechanism
and efficiency of three types of deodorants,
namely activated carbon (AC), maltosyl
cyclodextrin (MCD) and apple polyphenol
(AP), in reducing the “boiled heavy
odour” of saccharified sweet potato juice
was investigated by researchers at USA and
Japan. Among the three deodorants
studied, AC was the most efficient at
removing the off-odour of saccharified
Vol 6(6) November-December 2007
sweet potato juice. MCD is effective at
stabilizing and solubilising the functional
compounds such as β-carotene, although
it did not deodorize the odour as much
as AC. Based on the results it is suggested
that MCD may serve as an effective
deodorant against off-odours of
intermediate substances formed during
the production of functional sweet potato
juice [Tamaki Kazuhiko, Tamaki Takeshi and
Suzuki Yoshitake, Deodorisation of off-odour during
sweet potato juice production by employing physical
and chemical deodorants, Food Chem, 2007,
105 (2), 454-461].
459
Beverage
Goat and sheep milk products
other than cheeses and yoghurt
The use of goat and sheep milk for manufacture of different
milk and milk products is increasing, although the proportion is much
less compared to cow and buffalo milk worldwide, but it is much better
organized in some countries than in others. Manufacturing of goat and
sheep milk commercially or artisanally on the farm for direct sales is
done successfully for pasteurized beverage, UHT (ultra high temperature),
evaporated milk, ice cream, milk powder, traditional goat milk products,
even soaps, lotions and sweets, besides the popular cheeses and yoghurt.
The problem of “goaty” or “mutton” flavour may exist in some areas, but
products such as ice cream, beverage milk and milk powder made from
goat or sheep milk, due to their nutritional and anti-allergenic properties,
can be a beneficial alternative milk product for children, young and sick
people. A review published by scientists at Department of Dairy Processing
and Operations, Anand Agricultural University, Anand, Gujarat, India covers
technological details of milk, cream, butter, ice cream, whey protein
concentrate, evaporated milk, UHT milk, milk powder, chhana, paneer,
and ghee from goat and sheep milk. The technology for utilization of
goat and sheep milk for commercial manufacture of products has received
some attention by research workers, but a great deal more work needs to
be undertaken to make the goat and sheep milk industry a viable partner
to the dairy cattle industry, and to assure, that producers of goat and
sheep milk get an adequate value for their milk, especially in areas where
only goats and sheep can survive. While application of goat or sheep
milk for cheese making is well known, few attempts have been made to
systematically study the use of goat or sheep milk for manufacture of
milk beverages, ice cream, butter, milk powder, condensed milk,
traditional products, even yoghurt, etc. Low daily volume, even of herd
bulk milk may be one of the reasons for the difficulty in establishing an
efficient processing industry of goat and sheep milk in many countries.
Large scale goat and/or sheep farms may not be a solution for solving this
situation in many regions with steep mountains and harsh desert, where
only goats and sheep can still support a farm family. It also remains to be
accepted, that technical knowledge generated through research with cow
milk is most often not applicable to the manufacture of quality products
from goat and sheep milk [Pandya AJ, and Ghodke KM, Goat and sheep milk
Quality and
shelf life of orange
juice aseptically
packaged in
PET bottles
The scientists at Technical University of
Cartagena, Agricultural Equipment and Food
Engineering Department, Spain did studies on
packaging of orange juice aseptically packaged
in bottles using different materials and filling
procedures was conducted to determine their
influence on the evolution of juice quality and
shelf life. Glass, multilayer PET (polyethylene
terephthalate) and monolayer PET bottles were
used. A characterisation study including DSC
thermograms, intrinsic viscosity and scanning
electron microscopy (SEM) photographs let
identify the different material used, taking part
in multi- and monolayer PET bottles for juice
packaging. Monolayer PET showed the lowest
retention of ascorbic acid during storage and shelf
life compared with multilayer PET and glass. But
the results revealed that if different factors, such
as oxygen scavenger, liquid nitrogen drop addition
in headspace during filling, aluminium foil seal
in screw-cap and refrigeration temperatures, are
combined with the monolayer PET bottles, orange
juice shelf life can be extended and values similar
to glass and multilayer PET bottles can be
obtained [Ros-Chumillas María, Belissario Yulissa, Iguaz
Asunción and López Antonio, Quality and shelf life of orange
juice aseptically packaged in PET bottles, J Food Eng,
2007, 79(1), 234-242].
products other than cheeses and yoghurt, Small Rumin Res, 2007, 68(1-2),
193-206].
460
Natural Product Radiance
Beverage
Detection of corn adulteration
in Brazilian Coffee
Coffea arabica Linn. has a
higher commercial value than C.
robusta Lind. due to its pronounced
flavour, and it is speculated that it is
adulterated with lower priced adulterants,
viz. cereals, coffee twigs, coffee, brown
sugar, etc.
The researchers at NCAUR,
Agricultural Research Service, U.S.
Department of Agriculture, North
University Street, Peoria, Illinois, USA
investigated a new method, based on highperformance liquid chromatography
(HPLC) tocopherol determination to
detect coffee adulteration by corn. During
studies tocopherols were analyzed in
six Brazilian coffee varieties, six
commercial coffee brands and one pure
commercial coffee sample intentionally
adulterated with roasted corn (5, 10 and
20%, w:w, corn:coffee) and six roasted
corn samples. On the basis of these values,
a new method to detect adulteration of
commercial coffee with corn has been
reported.
Percentages of α-, β-, γand δ-tocopherol determined by HPLC in
six coffee varieties were 29.0, 61.7, 3.3
and 6.0, respectively. Similar values were
obtained in six popular coffee brands. The
percentages of α-, γ- and δ-tocopherol
in six corn samples were 3.6, 91.3 and
5.1, respectively. These differences could
be applied to detect corn in a pure coffee
sample intentionally contaminated with
corn with the best result obtained with
γ-tocopherol. With this methodology, one
coffee brand was apparently adulterated
(8.9%), most likely with corn. Thus,
tocopherol fingerprinting offers the
potential to detect adulteration [Jham Gulab
N, Winkler Jill K, Berhow Mark A and Vaughn
Steven F, γ-Tocopherol as a Marker of Brazilian
Coffee (Coffea arabica L.) Adulteration by Corn,
J Agric Food Chem, 2007, 55(15),
5995 -5999].
Dietary fibre in brewed coffee
Coffee is one of the most widely
consumed and appreciated beverages for
its taste carbohydrates, minerals and
volatile compounds and the amounts of
these substances vary depending on coffee
bean origin, roasting grade, extraction
method and conditions, and cup
concentration. Hot water extractable
polysaccharides are the main high
molecular weight components of coffee
infusions and play an important role in
the viscosity of the brew, in the foam
stability of espresso coffee, and hence in
the retention of volatile substances. Dietary
Vol 6(6) November-December 2007
fibre (DF) is the non-digestible part of
vegetable foods and beverages and plays
an important role in nutrition and health.
Green and roasted coffee beans are rich
in DF and may pass into the brewed coffee
in the brewing process. Therefore, the
scientists at Department of Metabolism
and Nutrition, Madrid, Spain worked to
ascertain whether DF is a common
constituent of brewed coffee and whether
some phenolics (and their antioxidant
activity) are associated with this fibre.
During experiments a specific method to
determine dietary fibre in beverages
(enzymatic treatment plus dialysis) was
applied to the coffees brewed by the most
common methods (espresso, filter,
soluble); results showed that brewed
coffee contained a significantly higher
amount of soluble dietary fibre (0.470.75g/100 ml of coffee) than other
common beverages. Coffee dietary fibre
contains a large amount of associated
antioxidant phenolics (8.7-10.5 mg/100
ml of brewed coffee) [Díaz-Rubio M Elena
and Saura-Calixto Fulgencio, Dietary Fibre in
Brewed Coffee, J Agric Food Chem, 2007,
55(5), 1999 -2003].
461
Beverage
Inactivation of Saccharomyces cerevisiae and
Lactobacillus plantarum in orange juice
Yeasts and lactic acid bacteria are
the usual contaminants in orange juice
and responsible for decreasing the shelf
life of the product. Ultra high-pressure
homogenization has been shown to be an
alternative to the traditional thermal
pasteurisation of pumpable foods. Hence,
in a study on inactivation of
microorganism
contaminants
(Lactobacillus plantarum and
Saccharomyces cerevisiae) of orange
juice using dynamic ultra high process
technology was conducted by scientists at
Brazil. The product was pumped through
a homogeniser valve at 100MPa, 150MPa,
200MPa, 250MPa and 300MPa using two
synchronized overlapped intensifiers at a
flow rate of approximately 270mL/min.
The inlet temperature was kept at 10°C,
pH at 4.1 and soluble solids at 10.0°Bx.
After processing, the product was
immediately cooled to 4°C and the
microbiological count was determined.
The study showed that L. plantarum and
S. cerevisiae are sensible to ultra
high-pressure homogenisation treatment
and pressures higher than 250MPa were
able to completely destroy initial loads of
1.2×107UFC/ml of L. plantarum and
2.9×105UFC/ml of S. cerevisiae in
orange juice, making this technology a
promising way to nonthermally processing
of orange juice. It is of industrial interest
and relevance to evaluate the use of this
non-thermal emerging technology to
process fluid foods that may result into
better taste, optimum product
functionality, safety and quality
characteristics [Campos FP and Cristianini M,
Inactivation of Saccharomyces cerevisiae and
Lactobacillus plantarum in orange juice using
ultra high-pressure homogenisation, Innov Food
Sci Emerg Technol, 2007, 8(2), 226-229].
Biocontrol of Staphylococcus aureus
in curd manufacturing processes using bacteriophages
The current technologies
employed to inactivate bacterial pathogens
in foods are not always foolproof and,
therefore, new approaches for improving
food safety are necessary. The exploitation
of bacteriophages has great potential for
use as biocontrol agents in foods.
Therefore, researchers at Instituto de
Productos Lácteos de Asturias,
Villaviciosa, Asturias, Spain conducted
studies to determine the ability of specific
bacteriophages to inhibit S. aureus
growth in curd manufacturing processes.
Two lytic bacteriophages specific against
462
S. aureus were obtained by DNA random
deletion from the milk-isolated temperate
phages, φH5 and φA72. A cocktail of these
lytic phages, φ88 and φ35, at multiplicity
of infection (MOI) of 100, produced a
complete elimination of 3×106cfu/ml of
the pathogen in ultra-high-temperature
(UHT) whole milk at 37°C. Furthermore,
the frequency of emergence of
bacteriophage-insensitive mutants was
reduced up to 200-fold in the presence of
the two lytic phages compared with that
detected with the combination of the
temperate counterparts. The lytic phage
derivatives, added to milk, were able to
decrease rapidly the viable counts of
S. aureus during curd manufacture. In
acid curd, the pathogen was not detected
after 4h of incubation at 25°C, whereas
pathogen clearance was achieved within
1h of incubation at 30°C in renneted curd.
These results indicate that lytic
bacteriophages could be used as
biopreservatives in the manufacture of
particular dairy products [García Pilar
Madera, Carmen, Martínez Beatriz and Rodríguez
Ana, Biocontrol of Staphylococcus aureus in
curd manufacturing processes using bacteriophages,
Int Dairy J, 2007, 17 (10), 1232-1239].
Natural Product Radiance
Beverage
Lactobacillus helveticus fermented milk
reduces arterial stiffness
Fermented milk products with
casein-derived biologically active peptides
isoleucyl-prolyl-proline (Ile-Pro-Pro)
and valyl-prolyl-proline (Val-Pro-Pro)
attenuate the development of hypertension
in spontaneously hypertensive rats (SHR)
and reduce blood pressure in moderately
hypertensive subjects, partially by
angiotensin converting enzyme (ACE)
inhibition. Arterial stiffening is markedly
accelerated in hypertension and it is an
independent predictor of coronary heart
disease in essential hypertension. The
effect of Ile-Pro-Pro and Val-Pro-Pro on
arterial stiffness in hypertensive subjects
has not been studied earlier. Therefore,
researchers at Finland conducted studies
to evaluate whether the antihypertensive
effect of Lactobacillus helveticus
fermented milk containing Ile-Pro-Pro
and Val-Pro-Pro is related to reduced
arterial stiffness.
They evaluated the 10-weektreatment effect of L. helveticus
fermented milk containing the tripeptides
isoleucyl-prolyl-proline and valyl-prolylproline on ambulatory arterial stiffness
index (AASI) by using the ambulatory
24h blood pressure registration. The AASI
improved significantly in the peptide milk
group (P=0.043), but not in the placebo
group (P=0.47), suggesting a mechanism
for the antihypertensive effects of these
peptides. Thus, in addition to its
antihypertensive effects, fermented milk
has beneficial cardiovascular effects by
reducing arterial stiffness [Jauhiainen T,
Rönnback M, Vapaatalo H, Wuolle K, Kautiainen H
and Korpela R, Lactobacillus helveticus
fermented milk reduces arterial stiffness in
hypertensive subjects, Int Dairy J, 2007, 17 (10),
1209-1211].
Effect of processing on the composition and
microstructure of buttermilk
Buttermilk is the liquid phase
released during churning of cream in the
process of butter making. This liquid
phase contains most of the water-soluble
components of cream. The effect of cream
pasteurization on the composition and
microstructure of buttermilk after
pasteurization, evaporation and spraydrying was studied by researchers at STELA
Dairy Research Group, Institute for
Nutraceuticals and Functional Foods
(INAF), Université Laval, Quebec City, Que,
Canada and Dairy Products and Technology
Center, California Polytechnic State
University, San Luis Obispo, CA, USA. The
composition of milk fat globule
membrane (MFGM) isolated from
buttermilk samples was also
characterized. Pasteurization of cream
resulted in higher lipid recovery in the
buttermilk. Spray-drying of buttermilk had
a significant effect on phospholipid
content and composition. After spraydrying, the phospholipid content
decreased by 38.2% and 40.6%,
respectively in buttermilk from raw or
pasteurized cream when compared with
initial buttermilks. Pasteurization of
cream resulted in the highest increase in
whey protein recovery in MFGM isolates
compared with all other processing steps
applied on buttermilk. A reduction in
phospholipid content was also observed
in MFGM isolates following spray-drying
[Morin Pierre, Jiménez-Flores Rafael and Pouliot
Yves, Effect of processing on the composition and
microstructure of buttermilk and its milk fat globule
membranes, Int Dairy J, 2007, 17(10),
1179-1187].
Probiotic cultures for fortification in fruit juices
Researchers at Ireland examined
the suitability of probiotic cultures as fruit
juice supplements by assessing their acid
tolerance and technological robustness.
Vol 6(6) November-December 2007
Survival of Lactobacillus and
Bifidobacterium strains in orange juice
(OJ), pineapple juice (PJ) and cranberry
juice (CJ) was monitored. Probiotic
tolerance to thermal and non-thermal
processing was studied to determine the
feasibility of their addition to OJ prior to
pasteurisation. OJ fortified with probiotic
463
Beverage
cultures was subjected thermal
pasteurisation at 76°C for 30s and 90°C
for 1min in addition to a high pressure
treatment of 400MPa for 5min. Results
revealed that extensive differences exist
among probiotic strains regarding their
acid resistance. All of the strains screened
survived for longer in OJ and PJ compared
to CJ. L. casei DN-114 001, L. rhamnosus
GG and L. paracasei NFBC43338 displayed
the greatest robustness surviving at levels
above 107cfu/ml in OJ and above 106cfu/
ml in PJ for at least 12weeks. The ability
of health-promoting cultures to survive for
at least 12weeks in orange juice and
pineapple juice at commercially critical
levels renders them suitable strains for
exploitation. Their inclusion may enhance
the market potential of these already
successful beverages [Sheehan Vivien M, Ross
P and Fitzgerald Gerald F, Assessing the acid
tolerance and the technological robustness of
probiotic cultures for fortification in fruit juices,
Innov Food Sci Emerg Technol, 2007, 8 (2),
279-284].
Occurrence of conjugated linoleic acid in probiotic
yoghurts supplemented with fructo-oligosaccharide
Presently, Lactobacillus
acidophilus or bifidobacteria
Bifidobacterium animalis are
increasingly being incorporated into
yoghurt due to the health benefits of
these probiotic bacteria. Intestinal
microorganisms can produce conjugated
linoleic acid (CLA), and CLA supply
can be increased not only by consuming
CLA-enriched dairy products but also by
modifying the gut flora by introducing
high CLA-producing lactic acid.
Oligosaccharides, especially fructooligosaccharides (FOS) have received
much attention recently as functional food
ingredients. They are used to enhance the
survivability and colonization of probiotic
bacteria that are added to foods and may
affect the CLA occurrence in probiotic
yoghurts. Therefore, researchers at Turkey
carried out studies to determine the effect
of milk processing, addition of L.
acidophilus or B. animalis,
supplementation with FOS and storage on
CLA levels in regular set yoghurts.
A gas chromatographic
procedure was used for the analysis of CLA
isomers, c9t11-CLA and t10c12-CLA, in
yoghurts containing L. acidophilus or
B. animalis and/or 2% FOS. Two groups
of set yoghurts containing no supplement
or 2% FOS were manufactured using three
different starter cultures to determine the
effect of processing, starter culture type,
FOS supplementation and storage on CLA
content. It was observed that addition of
these bacteria contributed to significant
increases in the CLA content of yoghurt
and supplementation of milk with 2% FOS
resulted in an additional increase of CLA
in the yoghurts. The highest level of total
CLA was obtained in the product
containing FOS and B. animalis. It is
concluded that CLA levels could be
enhanced by probiotic bacteria with high
CLA-producing potential and FOS
supplementation during processing of
yoghurt. Total CLA content of the probiotic
yoghurts was stable over a 28 days storage
period [Akalin AS, Tokusoglu O, Gönç S and Aycan
S, Occurrence of conjugated linoleic acid in
probiotic yoghurts supplemented with
fructooligosaccharide, Int Dairy J, 2007, 17 (9),
1089-1095].
Production of free fatty acids and
conjugated linoleic acid in probiotic dahi
Several studies have revealed that
the addition of lactic acid bacteria (LAB)
to dairy products may contribute to the
production of free fatty acids (FFAs) by
lipolysis of milk fat. Moreover, LAB also
have the ability to produce conjugated
464
linoleic acid (CLA) from linoleic acid,
which has attracted much attention as a
novel type of beneficial functional lipid.
Therefore, the production of FFAs and CLA
in probiotic dahi containing
Lactobacillus acidophilus and
L. casei during fermentation and 10 days
of storage at 4°C was evaluated and
compared with control dahi by
researchers at National Dairy Research
Institute, Karnal, Haryana, India. The total
FFAs in terms of acid degree values
Natural Product Radiance
Beverage
significantly increased during fermentation
and storage of both types of dahi samples.
In addition, gas chromatographic analysis
of FFAs showed that butyric and linoleic
acids increased in the probiotic dahi
compared to control dahi during
fermentation and storage. Furthermore,
the CLA content also increased during
fermentation and remained stable during
storage, whereas no change was observed
in the control. Probiotic lactobacilli
appeared to increase the production of
FFAs by lipolysis of milk fat, and produced
CLA by using internal linoleic acid, which
Efficacy of whey protein to
ameliorate the toxic effects
of aflatoxins
Aflatoxins (AFTs) are secondary metabolites of some
mould strains of Aspergillus flavus and A. parasiticus that
frequently contaminate cereal crops. The physiological effects of
AFT consumption include liver damage characterized by
enlargement, release of enzymes into the blood and impaired
protein synthesis. Whey protein concentrates (WPCs) and isolates
are considered as functional food ingredients of important
nutritional and health effects. They represent a mixture of secreted
proteins with wide range of chemical, physical and functional
properties.
A study was conducted by researchers at National Research
Center, Dokki, Cairo, Egypt to assess the ability of whey protein
concentrate to protect against aflatoxicosis. Three groups of
Sprague-Dawley male rats were used. The control (a) was fed on
casein diet, the control (b) received the same diet contaminated
with aflatoxins (AFT; 2.5mg AFB1/kg). The AFT-contaminated diet
was supplemented with WPC and fed to the third group for 9
weeks. Compared with control (a) rats, those fed the contaminated
diet control (b) showed significant drop (P<0.05) in body weight
gains, food efficiency ratio (FER), an increase in the liver function
enzymes, malondialdehyde level and a decrease in blood
glutathione, plasma calcium, magnesium and potassium. Addition
of WPC to the AFT-contaminated diet realized better growth rate
and FER and improved the above biochemical parameters. These
findings indicate that whey proteins can alleviate some of the
toxic effects of AFT [Saleh Zeinab A, El-Garawany Gamaal A, Assem Fayza
and El-Shibiny Safinaz, Evaluation of the efficacy of whey protein to ameliorate
the toxic effects of aflatoxins in rats, Int Dairy J, 2007, 17 (7),
854-859].
Vol 6(6) November-December 2007
may confer nutritional and therapeutic
value to the product [Yadav Hariom, Jain
Shalini and Sinha PR, Production of free fatty
acids and conjugated linoleic acid in probiotic
dahi containing Lactobacillus acidophilus
and Lactobacillus casei during fermentation
and storage, Int Dairy J, 2007, 17(8),
1006-1010].
Flow behaviour of
inulin-milk beverages
Inulin is a natural component of several fruits and
vegetables. It is mainly obtained from chicory roots by an
extraction process with hot water, followed by purification
and crystallisation. In addition to its beneficial effects on
health, as a dietetic fibre and as a prebiotic ingredient,
inulin shows interesting technological properties, as a lowcalorie sweetener, as a fat substitute, or it can be used to
modify texture.
The effects of the addition of different types of
inulin (oligofructose, native and long chain) at different
concentrations (2, 4, 6, 8 and 10% w/w) on the flow
behaviour of milk beverages model systems were studied by
researchers in Spain. The flow of the inulin-milk solutions
was Newtonian, except for whole milk samples with higher
long chain inulin concentrations (8 and 10%), which were
shear thinning. All inulin-κ-carrageenan-milk samples were
shear thinning. The viscosity of 3.1% fat whole milk could
be approximated by skim milk with 4-10% short chain inulin
or with 6-8% native inulin or with 4-6% long chain inulin.
In κ-carrageenan-milk samples, the addition of inulin could
not replace the effect of milk fat on the viscosity of these
systems. The results showed that the effect of the inulin
average chain length and of the inulin concentration on
viscosity of milk beverages depended on the type of milk
(skimmed or whole) and on the addition or not of
κ-carrageenan [Villegas B and Costell E, Flow behaviour of inulinmilk beverages. Influence of inulin average chain length and of milk fat
content, Int Dairy J, 2007, 17 (7), 776-781].
465
Beverage
Loss of rutin and antioxidant activity of asparagus juice
Asparagus
(Asparagus
officinalis Linn., family Liliaceae) is a
green vegetable with high antioxidant
activity. As asparagus deteriorate quickly
after harvest, it is often processed to
extend its shelf-life. Asparagus juice could
be a potential product for human
consumption.
Researchers at Washington State
University, Pullman, WA, USA found that
a commercial pectolytic enzyme
preparation from Aspergillus niger
(pectinase AN) contained laccase activity
that decreased rutin content and
antioxidant activity of asparagus juice. They
investigated the effects of pH,
temperature, and concentration of
pectinase AN on pectinase AN’s laccase
activity to decrease rutin content and
antioxidant activity of asparagus juice.
Asparagus juice was incubated with
pectinase AN at different pH (3.2, 4.5 and
5.8), temperatures (25, 37 and 50°C) and
enzyme concentrations (0.1, 0.5 and 1%).
Rutin content and antioxidant activity of
samples was determined by HPLC and
2,2'-diphenyl-1-picrylhydrazyl (DPPH)
free radical method, respectively. The rate
of loss of rutin and antioxidant activity of
asparagus juice was smaller at pH 3.2 than
at pH 4.5 and pH 5.8, smaller for 0.1%
pectinase AN than 0.5% and 1% pectinase
AN. The rate of loss of rutin of asparagus
juice was greater at 25°C than at the other
two temperatures. Pectinase AN can
decrease rutin content and antioxidant
activity of asparagus juice at the selected
conditions. But rutin content and
antioxidant activity of asparagus juice
produced using pectinase AN could be less
decreased at pH 3.2 and 0.1% of enzyme
with less than 2h of incubation time. This
information was helpful for juice industry
to produce juices with high antioxidant
activity using pectinase AN [Sun Ting, Powers
Joseph R and Tang Juming, Loss of rutin and
antioxidant activity of asparagus juice caused by a
pectolytic enzyme preparation from Aspergillus
niger, Food Chem, 2007, 105 (1), 173-178].
Optimization of enzymatic prepress
treatment of elderberry juice
Researchers from Denmark
examined the effects of different,
statistically designed, enzymatic
maceration treatments on juice yield,
turbidity and phenol yield (total phenols
and total anthocyanins) in experimentally
produced elderberry (Sambucus nigra
Linn.) juice. Increased pectinolytic
enzyme dose, longer maceration time and
elevated reaction temperature all had
significantly positive effects on the juice
yield. Increased enzyme dose and
maceration temperature also increased
the yields of anthocyanins in the elderberry
juice, while none of the reaction
parameters affected the juice turbidity. The
juice yield was optimized further in a new
experimental template, made by using the
statistical steepest ascent optimization
466
method. In the new response surface
design template an optimal maceration
treatment giving maximal juice yield and
anthocyanin yields and low turbidity was
identified. With the optimal treatment with
a pectinolytic enzyme preparation,
Pectinex BE 3L, produced by a cloned
Aspergillus strain, a maximal juice yield
of 77%w/w of the berry mash, an
anthocyanin yield of 2380mg/kg fresh
berry mash and a turbidity level of 128
formazin nephelometric units (FNU) were
obtained. Enzymatic prepress treatment
generally decreased turbidity levels by 30%
as compared to pressing without prior
enzymatic treatment. A comparison of the
responses obtained after the optimal
enzymatic treatment with five different
pectinolytic enzyme preparations showed
that the Aspergillus niger preparation
Pectinex BE Color gave slightly better juice
and phenol yields and lower turbidity
levels than the other enzyme preparations
tested. The results demonstrated that juice
and phenolic yields in elderberry juice
could be improved with enzyme treatment
and that the optimal reaction conditions
for obtaining the best juice yield, highest
phenolics and lowest turbidity levels could
be rationally identified via statistical factor
level optimization [Landbo Anne-Katrine, Kaack
Karl and Meyer Anne S, Statistically designed two
step response surface optimization of enzymatic
prepress treatment to increase juice yield and lower
turbidity of elderberry juice, Innov Food Sci
Emerg Technol, 2007, 8 (1), 135-142].
Natural Product Radiance
Beverage
ACE-inhibitory activity of probiotic yoghurt
Fermented milk products, in
addition to providing both energy and
nutrients, are an excellent source of
bioactive peptides. Among various
bioactive peptides, the antihypertensive
peptides or angiotensin-converting enzyme
inhibitors (ACE-I) are the most widely
studied. ACE inhibition leads to a decrease
in the level of the vasoconstricting
peptide, angiotensin II and a
corresponding increase in the level of the
vasodilatory peptide, bradykinin,
therefore, yielding an overall reduction in
blood pressure. These biologically active
peptides could represent a healthier and
natural alternative for the ACE-I drugs.
Although yoghurt culture exhibited a
substantial level of proteolytic activity in
the control yoghurt, the amount of
liberated peptides was further enhanced
by the action of probiotic bacteria in the
probiotic yoghurt. Consequently, the
increased proteolytic activity could have
resulted in better survival of some probiotic
organisms in yoghurt during storage.
Researchers of Australia assessed
in vitro ACE-I activity of peptide fractions
from different yoghurt batches. Inhibition
of ACE activity resulted in an overall
antihypertensive effect. Yoghurts were
prepared either using a sole yoghurt culture
including Lactobacillus delbrueckii
ssp. bulgaricus Lb1466 and
Streptococcus thermophilus St1342,
or L. acidophilus L10, L. casei L26 and
Bifidobacterium lactis B94 in addition
to yoghurt culture. ACE-I activity was
determined at weekly intervals during 28
days of cold storage. Peptide fractions
showing high ACE-I activity were further
purified using multiple-steps of RP-HPLC.
All probiotic yoghurts showed appreciable
ACE-I activity during initial stages of
storage compared with the control
yoghurt, with a significant (P<0.05)
decrease afterwards. The ACE-I activity
ranged from IC50 of 103.30-27.79µg/ml
with the greatest ACE inhibition achieved
during first and third week of storage. The
in vitro ACE-I activity could be related to
the peptide liberation via degradation of
caseins. In total, 8 ACE-I peptides were
characterized originating from αs2-casein
(1), κ-casein (2) and β-casein, of which
two well-known ACE-inhibiting peptides,
namely Val–Pro–Pro (VPP) and Ile–Pro–
Pro (IPP) were identified. These peptides
are already used in commercial products.
However, further studies are necessary to
elucidate the formation and degradation
mechanism of these peptides. The
development of yoghurt containing higher
concentrations of released bioactive ACE
inhibitors and viable probiotics may
deliver health benefits to consumers
[Donkor ON, Henriksson A, Singh TK,
Vasiljevic T and Shah NP, ACE-inhibitory activity of
probiotic yoghurt, Int Dairy J, 2007, 17 (11),
1321-1331].
Use of probiotic and dairy cultures in
fermented soymilk
The metabolic activities of
Lactobacillus acidophilus (LAFTI® L10
and La4962) Bifidobacterium (lactis
LAFTI ® B94 and longum Bl536),
Lactobacillus casei (LAFTI® L26 and
Lc279), Lactobacillus delbrueckii ssp.
bulgaricus Lb1466 and Streptococcus
thermophilus St1342 were assessed in
soymilk by researchers of Australia.
Strains were initially analyzed for
α-galactosidase activity and organic acid
production in MRS broth at 37°C.
Consequently, soymilk was fermented with
each strain and cell growth, production
Vol 6(6) November-December 2007
of organic acid, metabolism of
oligosaccharides and proteolytic and
ACE-inhibitory activities were assessed
during 48h of incubation at 42°C. All
strains exhibited variable α-galactosidase
activity, with Bifidobacterium lactis
B94 showing the highest activity. The
oligosaccharide metabolism depended on
α-galactosidase activity. B. lactis B94,
S. thermophilus St1342 and
L. acidophilus La4962 reduced raffinose
substantially by 77.4, 64.5 and 55.9%,
respectively. All strains reached the desired
therapeutic level of 108cfu/ml in soymilk
after 48h at 42°C. The hydrolysis of protein
in soymilk likely depended on strain
(P<0.0001) and time (P<0.0001). The
strains also released bioactive peptides
with ACE-inhibitory activities between
17 and 43%. Thus, fermented soymilk
could be converted into a rich functional
product containing probiotics and
bioactive compounds [Donkor Osaana N,
Henriksson A, Vasiljevic T and Shah NP,
α-Galactosidase and proteolytic activities of selected
probiotic and dairy cultures in fermented soymilk,
Food Chem, 2007, 104 (1), 10-20].
467
Download PDF
Similar pages