1,721,084 research outputs found
Understanding factors influencing starch degradation dynamics in monogastrics: in vitro and in vivo approaches
No full textLo scopo del presente lavoro è stato quello di esaminare il potenziale di idrolisi e degradabilità dell’amido dei cereali e co-prodotti e di valutare gli aspetti collegati. L’approccio utilizzato comprende sia test in vitro che in vivo. In particolare:
- Una serie d’indagini in vitro ha fornito dati sul potenziale di degradabilità enzimatica dell’amido dei cereali e co-prodotti considerando sia l’influenza della struttura dell’amido, del tipo di cereale, del rapporto amilosio:amilopectina, del processo termico, dell’insilamento, dello stadio di maturazione e delle pratiche agronomiche.
- Una valutazione funzionale basata sul calcolo del potenziale di degradabilità enzimatica dell’amido tramite la stima dell’indice glicemico in vitro, combinata con un approccio matematico di modellizzazione dei dati ottenuti, è stata proposta per fornire un metodo efficace di screening dei materiali amidacei utilizzati comunamente nella formulazione per diete destinate ai suini.
- Un esperimento in vitro è stato condotto per investigare la risposta glicemica post-prandiale in suini alimentati con diete che differivano nel potenziale di idrolisi enzimatica.
Infine, considerando la crescente attenzione dei nutrizionisti sulla matrice proteica dei cereali (con particolare importanza data alle prolammine), i metodi comunemente utilizzati per le tecniche di estrazione delle prolammine sono stati confrontati e ri-investigati.In the present work, it has been attempted to examine the variability in starch hydrolysis and digestion from cereal grains and co-products and to study aspects related, in order to give a better understand of the science behind the differences in grains/feeds starch digestion potential. The general approach was to use a combination of in vitro and in vivo techniques. In particular:
- A series of in vitro investigations has provided data on the degradation potential of starch from cereal grains and co-products considering the influence of starch structure, cereal type, amylose-amylopectin ratio, heat processing, ensiling, stage of maturity and of agricultural practices.
- A laboratory-based functional evaluation of starch value of cereal grains based on a predicted glycemic index approach, combined with a mathematical first-order exponential model, has been proposed in order to allow an efficient screening of starchy-materials entering in the pig diet formulation.
- An in vivo experiment has been undertaken to investigate the postprandial plasma glucose response in pigs fed diets containing starch with a wide range in in vitro digestion patterns.
Lastly, taking into account the increasing attention of swine nutritionists on prolamin proteins, the most commonly used prolamin extraction procedures were compared and reinvestigated, in order to get useful information for routine lab analysis
Can different types of resistant starch influence the in vitro starch digestion of gluten free breads?
No full textnot availabl
Gas production and starch degradability of corn and barley meals differing in mean particle size
No full textThe objective of this study was to verify the effect of
mean particle size (mPS) on both gas production and
in vitro rumen starch degradability (IVSD) of corn and
barley meals (Cm and Bm, respectively). Batches of
the same Cm or Bm were separately processed through
2 different mills (i.e., a cutter mill or a rotor speed mill)
equipped with or without different screens to achieve
different mPS for each tested meal. Samples were analyzed
accordingly to a completely randomized design
and the main tested effect of model was mPS (n = 11,
from 0.46 to 3.50 mm mPS for Cm or n = 10, from 0.11
to 2.98 mm mPS for Bm). For both in vitro assays, the
rumen inocula were collected from 2 rumen-fistulated
Holstein lactating dairy cows fed a total mixed ration
with 16.2% crude protein, 28.5% starch, and 35.0%
neutral detergent fiber on a dry matter basis. To fit gas
production data, 1-pool exponential model and 1-pool
or 2-pool Gompertz models were adopted. The rate of
gas production decreased and lag increased by increasing
mPS of both Cm and Bm, irrespective of adopted
1-pool models. When the 2-pool Gompertz model was
used to fit gas production data, a shift of particles from
fast to slow fermentable pools was measured by increasing
mPS. In particular, the ratio between fast and slow
final volumes ranged from 0.90 at 0.11 mm mPS to 0.10
at 2.98 mm mPS for Bm. For Cm, the ratio between
fast and slow final volumes decreased quadratically
by increasing mPS, with the highest value (i.e., 0.58)
measured at the lowest tested mPS. Values lower than
0.10 were measured for mPS greater than 1.93 mm for
Cm. Concerning IVSD data, linear decreases in rate
of starch degradation equal to −0.049 or −0.092 h−1
for each 1-mm increase in mPS were achieved for Cm
and Bm, respectively. The 7-h IVSD decreased by 6.3
or 6.5% starch for each 1-mm increase in mPS of Cm
or Bm, respectively. Present findings supported the
hypothesis that different particle sizes within the same
starch source represent an important factor influencing
both fermentation kinetic parameters and IVSD
Chemical composition and rumen degradability of three corn hybrids treated with insecticides against the european corn borer (Ostrinia nubilalis)
No full textThis experiment determined the chemical composition, rumen degradability (aNDF in
stalks and starch in kernels) and in vitro gas production of kernels from three corn hybrids
treated (TT) or not treated (control, CTR) with insecticides against the European corn borer
(ECB, Ostrinia nubilalis). Two whole-plant silage hybrids belonging to the FAO rating 600
and 700 maturity class (S600 and S700, respectively) and one selected for grain production
(G600, FAO rating 600, Dekalb-Monsanto Agricoltura S.p.A., Lodi, Italy) were sown in two
main plots (TT and CTR) of an experimental field. Two subsequent treatments of pyrethroids
(25 and 1.2 g/ha of cyfluthrin and deltamethrin, respectively) were applied to the TT plots.
The insecticide treatment reduced the number of damaged plants (4.5 broken plants/plot
versus 0.3 broken plants/plot, P<0.01) and increased the total grain yield by 11% (13.8 t/ha
versus 12.4 t/ha), while hybrids did not differ. ECB larvae which bored into the stalk tunnels
modified the chemical composition of stalks and kernels. In stalks, total sugars content (i.e.
glucose, fructose, sucrose) was about twice that in TT versus CTR plants (123 g/kg versus
60 g/kg DM, P<0.01), while aNDF content was higher in CTR stalks (765 versus 702 g/kg
DM, P<0.01). DM degradability after 48 h of incubation of stalks was higher in TT than in
CTR, both in vitro (0.360 versus 0.298, P<0.01) and in situ (0.370 versus 0.298, P<0.05), while
there were no differences in aNDF degradability. Kernels from TT plots contained less DM
(615 g/kg versus 651 g/kg, P<0.01) and more CP (84 g/kg and 78 g/kg DM, P<0.05) than those
from CTR plots, while in situ rumen starch disappearance and in vitro gas production were
similar. Corn hybrid selected for yield of grain (G600) differed from S600 and S700 due to a
higher (P<0.01) content of aNDF, ADF and lignin(sa) in the stalks, and a higher starch content
(696 g/kg versus 674 and 671 g/kg DM, P<0.01) and CP (87 g/kg versus 77 and 76 g/kg
DM, P<0.05) in grain. The G600 hybrid produced stalks with a lower (P<0.01) aNDF rumen
degradability than the S600 and S700.
On field ECB insecticide treatment improved corn grain yield, reduced broken plants and
increased stalk sugars content at harvestin
Reducing the glycaemic index and increasing the slowly digestible starch content in gluten-free cereal-based foods: a review
No full textCommercially available gluten-free (GF) cereal-based foods are generally characterised by a lower nutritional quality than their gluten-containing counterparts, relatively lower resistant starch (RS) content, along with higher glycaemic index (GI) often being reported. To overcome this nutritional imbalance, extensive research has been conducted to investigate the preparation of a new generation of staple GF products. This review reported the main strategies currently adopted in GF cereal-based food recipes to formulate products with overall slowly digestible starch properties. They are mainly obtained by the utilisation of alternative ingredients to be incorporated into standard food formulation (including native starch and GF flours) or by technological treatments that may contribute to impact starch digestibility. Considering data from in vitro digestion trials, indications suggested that, aiming to obtain a RS content of about 5% (dry weight) and lowering the in vitro GI values, the minimum high amylose starch (amylose >60%) replacement level in GF bread and cookie formulations should be in the order of 20% by weight of total flours. Overall, with respect to un-substituted GF foods, two- to three-times higher RS contents, along with a parallel in vitro GI decrease (up to â50%), were obtained for GF pasta and ready-to-eat snacks enriched with legume flours at inclusion levels from 40% to 100% by weight of total flours. The use of flours from pseudocereals (e.g., quinoa, amaranth and buckwheat) with and without sourdough did not always guarantee favourably slowly digestible starch GF foods
Technical note: Quantification of zeins from corn, high-moisture corn, and corn silage using a turbidimetric method: Comparative efficiencies of isopropyl and tert-butyl alcohols
No full textZeins are corn endosperm storage proteins that encapsulate
starch granules into a protein matrix, which
can act as a barrier to starch accessibility and digestion.
Laboratory methods to quantify zein are seldom
used because they are considered arduous and timeconsuming.
A recently published rapid turbidimetric
method (mTM) was reinvestigated by changing the
solution originally used for the zein solubilization step.
In particular, the aim was to explore whether, and to
what extent, the use of tert-butyl alcohol (t-BuOHmTM)
in lieu of isopropyl alcohol (i-PrOH-mTM) was
able to improve the quantification of zeins from dry
corn, high-moisture corn, and corn silage samples. The
nature of the alcohol influenced the zein extraction
values, and t-BuOH-mTM gave higher zein values in
corn (3.6 vs. 3.3 g/100 g of dry matter) and corn silage
samples (1.2 vs. 0.9 g/100 g of dry matter) compared
with i-PrOH-mTM. In contrast, similar zein extraction
values were obtained for high-moisture corn (2.1 vs.
1.9 g/100 g of dry matter, respectively). Sodium dodecyl
sulfate-PAGE analysis revealed no contamination
by nonzein proteins with the use of tert-butyl alcohol.
Overall, these findings indicated that tert-butyl alcohol
has a greater ability to solubilize zein compared with
isopropyl alcohol and thus the t-BuOH-mTM allowed
greater extraction of zeins. Considering the growing
interest of animal nutritionists in zein proteins, such
results should provide useful informatio
Effect of nitrogen fertilization on chemical composition and rumen fermentation of different parts of plants of three corn hybrids
No full textThe experiment compared reductions in the level of N fertilisation of corn crop (i.e., no N
fertilisation; 0-N, or 150 kg of N/ha; 150-N) with those currently adopted in the Po valley of
North Italy (i.e., 300 kg of N/ha; 300-N) on chemical and nutritional characteristics of grain,
stalks and leaves in corn hybrids selected for whole plant silage production (i.e., FAO 700
maturity). Grain composition and starch availability for digestion was examined at three
stages of maturity of the kernels (i.e., 1⁄2 milk line,3⁄4milk line and black layer). One hybrid
had a lower grain yield (15.2 versus 16.0–16.8 tonnes DM/ha; P<0.05), while all hybrids
were similar in whole plant yield. Levels of N fertilization of 150-N and 300-N resulted
in similar yields of grain and whole plants, which were 17 and 33% higher, respectively
(P<0.01) than 0-N plots. Hybrids were similar in chemical composition. Reduction of N
fertilisation from 300-N to 0-N lowered (P<0.01) the crude protein content in grains, leaves
and stalks (P<0.05 in apical part of stalks) and reduced the zein content in grains from
43 to 33 g/kg DM (P<0.01). Vitreousness of grains was not influenced by N fertilisation,
while the highest (P<0.01) gas production was at the short incubation time of 2 h for grains
with 300-N. Reduction of fertilisation levels (i.e., 150-N and 0-N versus 300-N) lowered
(P<0.01) NDF degradation in the basal stalks (0.385 and 0.392 versus 0.412) and leaves
(0.604 and 0.620 versus 0.622). Stage of maturity of grain did not interact with the N level of
fertilization, and advanced maturity was associated with a marked increase (P<0.01) in zein
content from 36 to 49 g/100 g CP and in grain vitreousness from 31 to 40 g/100 g endosperm
and with a reduction of the gas production, which had the lowest values at 2 and 48 h
(P<0.01) of incubation. Overall, reductions in N fertilisation of corn crop slightly lowered
the crude protein content and fiber degradation of different part plants. In grains, the lowest
N fertilisation (i.e., 0-N) reduced the zein content
Resistant Starch from Isolated White Sorghum Starch: Functional and Physicochemical Properties and Resistant Starch Retention After Cooking. A Comparative Study
No full textIn an effort to promote the formation of resistant starch (RS), four different modification methods are applied to isolated white sorghum (WS) starch by subjecting the latter to heat‐moisture treatment (RSa), annealing (RSb), hydrolysis through pullulanase debranching enzyme (RSc), and dual autoclaving‐cooling cycles (RSd). Functional and physicochemical properties, individual RS content, and the behavior after cooking in terms of apparent RS retention (aRSr) of samples (i.e., WS, RSa, RSb, RSc, and RSd) are compared. Differences in thermal and pasting properties, in the ratio of ordered starch to amorphous starch, along with lower solubility and swelling power values, and greater water absorption capacity are measured in the four RS ingredients when compared to native WS starch. All the four modification methods prove to be similarly effective in increasing the amount of RS with respect to native WS starch, with an average 30% increase. However, based on the aRSr values, analyses revealed that the greater heat stability after cooking was obtained for RSb (93.7%) and decreased in the order of RSb>RSc>RSa = RSd>WS. Present results shed light on the properties of modified WS starch as a potential heat‐stable source of RS for food applications
Gluten free rice cookies with resistant starch ingredients from modified waxy rice starches: Nutritional aspects and textural characteristics
No full textExperimental gluten-free (GF) rice cookies were formulated with 100% rice flour (CTR) or by substituting 50% of rice flour with native waxy rice starch (WRS) or with three different resistant starch (RS) ingredients obtained from debranched, annealed or acid and heat-moisture treated WRS (RSa, RSband RSc, respectively). Chemical composition, in vitro starch digestibility and physical and textural characteristics were carried out. Among cookies, RSa-cookies had the highest total dietary fibre content, the lowest rapidly digestible starch and the highest RS contents. All the three RS preparations have proved effective in increasing the proportion that tested as RS with respect to native WRS. However, the estimated RS loss for each applied RS ingredients caused by the baking process followed the order of RSa< RSc< RSb. Last, the lowest vitro glycaemic index value was measured for RSa-cookies. Among cookies, differences in colour and hardness were reported. The partial replacement of commercial rice flour with RSacould contribute to formulate GF cookies with higher dietary fibre content and likely slowly digestible starch properties more than equivalent amounts of RSband RSc
Exploring the bioaccessibility of polyphenols and glucosinolates from Brassicaceae microgreens by combining metabolomics profiling and computational chemometrics
No full textMicrogreens constitute natural -based foods with health -promoting properties mediated by the accumulation of glucosinolates (GLs) and phenolic compounds (PCs), although their bioaccessibility may limit their nutritional potential. This work subjected eight Brassicaceae microgreens to in vitro gastrointestinal digestion and large intestine fermentation before the metabolomics profiling of PCs and GLs. The application of multivariate statistics effectively discriminated among species and their interaction with in vitro digestion phases. The flavonoids associated with arugula and the aliphatic GLs related to red cabbage and cauliflower were identified as discriminant markers among microgreen species. The multi-omics integration along in vitro digestion and fermentation predicted bioaccessible markers, featuring potential candidates that may eventually be responsible for these functional foods' nutritional properties. This combined analytical and computational framework provided a promising platform to predict the nutritional metabolome-wide outcome of functional food consumption, as in the case of microgreens
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