Simple Method for Preparing Starch Inclusion Complexes with Enhanced Amylolysis Resistance and Antioxidant Properties.

Slow-digesting starch with bioactive functionality has been attracting much interest with the increasing incidence of type-2 diabetes and other diet-related illnesses. The present study demonstrates a simple method for preparing a starch inclusion complex with reduced enzymic digestion and enhanced antioxidant activities using debranched pea starch (PS) and 10-gingerol (10G). Enzymically debranched starch complexed more 10G and formed more structurally ordered starch-10G complexes compared to PS that had not been debranched. Debranching for 6 h resulted in starch with better complexing ability for 10G than starches debranched for longer times. The debranched starch-10G complexes had higher antioxidant activities and a much slower in vitro enzymic digestion profile (rate and hydrolysis extent) than the 10G complex prepared with starch that was not debranched. Our study demonstrates that debranched pea starch-10G complexes with slow-digesting and antioxidant properties are likely to be of interest for developing ingredients for healthier food choices.

Novel Type of Slowly Digested Starch Complex with Antioxidant Properties.

With the increasing number of diabetic patients in the world, there is an urgent requirement to reduce the incidence of diabetes. It is considered that a viable prophylactic treatment for type 2 diabetes mellitus is to reduce starch digestibility and oxidative stress. In this study, a novel type of slowly digested starch [pea starch (PS)-gingerol complex] was fabricated to evaluate its in vitro enzymatic digestibility and antioxidant activities. Theoretical and experimental analyses showed that PS can encapsulate gingerols with long alkyl chains to form starch-gingerol complexes, which are further stacked into a mixture of V6- and V7-crystallites. These complexes, in particular the PS-10-gingerol complex, showed high resistance to amylolysis and good antioxidant activities. This study demonstrates that these novel starch-gingerol complexes have the potential to deliver antioxidants encapsulated in starch with slow-digesting properties and reduce oxidative stress. Moreover, this new type of slowly digested starch with antioxidant properties showed great potential in the prevention of type 2 diabetes.

Novel Approach for Quantitative Characterization of Short-Range Molecular Order in Gelatinized Starch by X-ray Diffraction.

A novel quantitative method was developed to characterize short-range molecular order in gelatinized wheat and potato starches using X-ray diffraction (XRD). Gelatinized starches with different amounts of short-range molecular order and amorphous starches with no short-range molecular order were prepared and characterized by the intensity and area of Raman spectral bands. The degree of short-range molecular order in the gelatinized wheat and potato starches decreased with increasing water content used for gelatinization. By comparing XRD patterns of gelatinized and amorphous starch, the XRD peak at 33° (2θ) was shown to be typical of gelatinized starch. The relative peak area (RPA), intensity, and full width at half-maximum (FWHM) of the XRD peak at 33° (2θ) decreased with the increase in water content for gelatinization. We propose that the RPA of the XRD peak at 33° (2θ) can be used to quantify the amount of short-range molecular order in gelatinized starch. The method developed in this study will help to explore and understand the relationship between the structure and functionality of gelatinized starch in food and nonfood applications.

Methods for characterizing the structure of starch in relation to its applications: a comprehensive review.

Starch is a major part of the human diet and an important material for industrial utilization. The structure of starch granules is the subject of intensive research because it determines functionality, and hence suitability for specific applications. Starch granules are made up of a hierarchy of complex structural elements, from lamellae and amorphous regions to blocklets, growth rings and granules, which increase in scale from nanometers to microns. The complexity of these native structures changes with the processing of starch-rich ingredients into foods and other products. This review aims to provide a comprehensive review of analytical methods developed to characterize structure of starch granules, and their applications in analyzing the changes in starch structure as a result of processing, with particular consideration of the poorly understood short-range ordered structures in amorphous regions of granules.

Reconstructing Neanderthal diet: The case for carbohydrates.

Evidence for plants rarely survives on Paleolithic sites, while animal bones and biomolecular analyses suggest animal produce was important to hominin populations, leading to the perspective that Neanderthals had a very-high-protein diet. But although individual and short-term survival is possible on a relatively low-carbohydrate diet, populations are unlikely to have thrived and reproduced without plants and the carbohydrates they provide. Today, nutritional guidelines recommend that around half the diet should be carbohydrate, while low intake is considered to compromise physical performance and successful reproduction. This is likely to have been the same for Paleolithic populations, highlighting an anomaly in that the basic physiological recommendations do not match the extensive archaeological evidence. Neanderthals had large, energy-expensive brains and led physically active lifestyles, suggesting that for optimal health they would have required high amounts of carbohydrates. To address this anomaly, we begin by outlining the essential role of carbohydrates in the human reproduction cycle and the brain and the effects on physical performance. We then evaluate the evidence for resource availability and the archaeological evidence for Neanderthal diet and investigate three ways that the anomaly between the archaeological evidence and the hypothetical dietary requirements might be explained. First, Neanderthals may have had an as yet unidentified genetic adaptation to an alternative physiological method to spare blood glucose and glycogen reserves for essential purposes. Second, they may have existed on a less-than-optimum diet and survived rather than thrived. Third, the methods used in dietary reconstruction could mask a complex combination of dietary plant and animal proportions. We end by proposing that analyses of Paleolithic diet and subsistence strategies need to be grounded in the minimum recommendations throughout the life course and that this provides a context for interpretation of the archaeological evidence from the behavioral and environmental perspectives.

Starch-lipid and starch-lipid-protein complexes: A comprehensive review.

Physical interactions often occur between major food components during food processing. These interactions may involve starch, lipids, and proteins forming V-type starch-lipid complexes or ternary starch-lipid-protein complexes of larger molecular size and greater structural order. Complexes between starch and lipids have been the subject of intensive research for over half a century, whereas the study of starch-lipid-protein complexes is a relatively new field with only a limited amount of knowledge being gained so far. The formation of these complexes can significantly affect the functional and nutritional properties of finished food products in terms of flavor, texture, shelf life, and digestibility. This article provides a comprehensive review of starch-lipid and starch-lipid-protein complexes, including their classification, factors affecting their formation and structure, and preparative and analytical methods. The review also considers how complexes affect the physicochemical and functional properties of starch, including digestibility, and potential applications in the food industry.

Pleistocene dental calculus: Recovering information on Paleolithic food items, medicines, paleoenvironment and microbes.

Dental calculus is now widely used to recover information on items ingested in the past. It is particularly valuable in the earlier Paleolithic, where recovered data may represent the only evidence for plant use. Several recovery methods are used and each one produces different results. Biomolecular markers and genetic material recovered from dental calculus is providing new data on identifiable dietary and medicinal items and human microbial communities. The recovery of microfossils, in particular, starch granules, has triggered a new awareness of the role of plants in the diet throughout the Paleolithic. However, the minute amount of material recovered has little relationship with food eaten during a person's life, while salivary amylase breaks down cooked starch. Therefore, broader dietary interpretations and detection of cooked food are problematic. The study of ancient dental calculus holds great potential to recover information about past lives, within realistic parameters.

Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe's oldest hominin at Sima del Elefante, Spain.

Sima del Elefante, Atapuerca, Spain contains one of the earliest hominin fragments yet known in Europe, dating to 1.2 Ma. Dental calculus from a hominin molar was removed, degraded and analysed to recover entrapped remains. Evidence for plant use at this time is very limited and this study has revealed the earliest direct evidence for foods consumed in the genus Homo. This comprises starchy carbohydrates from two plants, including a species of grass from the Triticeae or Bromideae tribe, meat and plant fibres. All food was eaten raw, and there is no evidence for processing of the starch granules which are intact and undamaged. Additional biographical detail includes fragments of non-edible wood found adjacent to an interproximal groove suggesting oral hygiene activities, while plant fibres may be linked to raw material processing. Environmental evidence comprises spores, insect fragments and conifer pollen grains which are consistent with a forested environment.

Beyond food: The multiple pathways for inclusion of materials into ancient dental calculus.

Dental calculus (mineralized dental plaque) was first recognised as a potentially useful archaeological deposit in the 1970s, though interest in human dental calculus as a resource material has increased sharply in the past few years. The majority of recent research has focused on the retrieval of plant microfossils embedded in its matrix and interpretation of these finds as largely the result of deliberate consumption of plant-derived food. However, while most of the material described in published works does represent food, dental calculus is in fact a "depositional environment" as material can enter the mouth from a range of sources. In this respect, it therefore represents an archaeological deposit that can also contain extensive non-dietary debris. This can comprise a wide variety of cultural and environmental material which reaches the mouth and can become embedded in dental calculus through alternative pathways. Here, we explore the human behaviors and activities besides eating that can generate a flux of particles into the human mouth, the broad range of additional cultural and environmental information that can be obtained through the analysis and contextualisation of this material, and the implications of the additional pathways by which material can become embedded in dental calculus.

Effect of acid hydrolysis on starch structure and functionality: a review.

Acid hydrolysis is an important chemical modification that can significantly change the structural and functional properties of starch without disrupting its granular morphology. A deep understanding of the effect of acid hydrolysis on starch structure and functionality is of great importance for starch scientific research and its industrial applications. During acid hydrolysis, amorphous regions are hydrolyzed preferentially, which enhances the crystallinity and double helical content of acid hydrolyzed starch. This review discusses current understanding of the effect of acid hydrolysis on starch structure and functionality. The effects of acid hydrolysis on amylose content, chain length distribution of amylopectin molecules, molecular and crystalline organization (including lamellar structure) and granular morphology are considered. Functional properties discussed include swelling power, gelatinization, retrogradation, pasting, gel texture, and in vitro enzyme digestibility. The paper also highlights some promising applications of acid hydrolyzed starch (starch nanocrystals) in the preparation of biodegradable nanocomposites, bio-hydrogen, and slowly digestible starch-based healthy foods.

Discovery of a low-glycaemic index potato and relationship with starch digestion in vitro.

Potatoes are usually a high-glycaemic index (GI) food. Finding a low-GI potato and developing a screening method for finding low-GI cultivars are both health and agricultural priorities. The aims of the present study were to screen the commonly used and newly introduced cultivars of potatoes, in a bid to discover a low-GI potato, and to describe the relationship between in vitro starch digestibility of cooked potatoes and their in vivo glycaemic response. According to International Standard Organisation (ISO) guidelines, seven different potato cultivars were tested for their GI. In vitro enzymatic starch hydrolysis and chemical analyses, including amylose content analysis, were carried out for each potato cultivar, and correlations with the respective GI values were sought. The potato cultivars had a wide range of GI values (53-103). The Carisma cultivar was classified as low GI and the Nicola cultivar (GI = 69) as medium GI and the other five cultivars were classified as high GI according to ISO guidelines. The GI values were strongly and positively correlated with the percentage of in vitro enzymatic hydrolysis of starch in the cooked potatoes, particularly with the hydrolysis percentage at 120 min (r 0·91 and P <0·01). Amylose, dietary fibre and total starch content was not correlated with either in vitro starch digestibility or GI. The findings suggest that low-GI potato cultivars can be identified by screening using a high-throughput in vitro digestion procedure, while chemical composition, including amylose and fibre content, is not indicative.

Key structural factors that determine the in vitro enzymatic digestibility of amylose-complexes.

The effects of complexing conditions on the formation of amylose-lipid-protein complexes and relationships between structure and digestion of amylose-lipid and amylose-lipid-protein complexes were poorly understood. The objective of this study was to investigate the effects of complexing time (0, 0.5, 2, 4 and 6 h) and temperature (60, 70, 80, 90 and 100 °C) on the structure and in vitro amylolysis of amylose-lauric acid (AM-LA) and amylose-lauric acid-ß-lactoglobulin (AM-LA-ßLG) complexes, and to understand the relationships between structure and in vitro digestiblity of these complexes. Longer complexing time and higher complexing temperature promoted the formation of greater amounts of the more stable type II crystallites than type I crystallites in both AM-LA and AM-LA-ßLG complexes, which in turn decreased the rate and extent of the complexes digestion to a greater extent. Correlation analyses between parameters for structure and digestion kinetics showed that both the quantity of AM-LA and AM-LA-ßLG complexes and the quality of their arrangement into V-type crystallites influenced their rate and extent of digestion. This study demonstrates that AM-LA and AM-LA-ßLG complexes can be prepared with designed structural and functional properties tailored for various applications.

Structural Factors That Determine the Amylolytic Properties of Starch-Lipid Complexes.

Structural factors that determine the amylolysis of starch-lipid complexes have remained unclear. Understanding the relationship between the structure and amylolysis of starch-lipid complexes is important for the design and preparation of complexes with predictable digestibility. In this study, the multiscale structures and amylolytic properties of complexes formed under different conditions between debranched high-amylose starch (DHAMS) and lauric, myristic, palmitic, and stearic acids were investigated. Higher complexing temperatures facilitated the formation of DHAMS-fatty acid (FA) complexes, especially the more stable type II crystallites. Longer complexing times also promoted the formation of complexes and the type II crystallites, except for DHAMS-lauric acid (LA). Molecular dynamics simulations showed that the binding free energy for the formation of DHAMS-LA complexes (10 kJ/mol) was lower than those for the other three DHAMS-FA complexes (20-50 kJ/mol), accounting for the lower stability of DHAMS-LA complexes at longer complexing times. The rate and extent of enzymatic digestion of the DHAMS-FA complexes were much lower in comparison to those of gelatinized HAMS. Correlation analyses showed that the rate and extent of enzymic digestion of DHAMS-FA complexes were mainly determined by the degree of crystallite perfection of the complexes.

The influence of short-range molecular order in gelatinized starch on the formation of starch-lauric acid complexes.

A model system of gelatinized wheat starch (GWS) and lauric acid (LA) was used to examine the effect of residual short-range molecular order in GWS on the formation of starch-lipid complexes. The extent of residual short-range molecular order, as determined by Raman spectroscopy, decreased with increasing water content or heating duration of gelatinization. The enthalpy changes, crystallinity, short-range molecular order and the in vitro enzymic digestion of GWS-LA complexes increased initially to a maximum and then declined as the short-range molecular order in GWS decreased, showing that there was an optimal amount of residual short-range molecular order in GWS for maximizing GWS-LA complexes formation. Below this optimum amount, the limited disruption of short-range molecular order may constrain the mobility of amylose chains for complexation with LA, whereas with excessive disruption above this amount the amylose chains may be too disorganized or entangled to form complexes with LA. The susceptibility of GWS-LA complexes to enzymatic hydrolysis was influenced by both long- and short-range structural order, and to a lesser extent the amounts of complexes. This study showed clearly the role of short-range molecular order in gelatinized starch in influencing the formation of GWS-LA complexes.

A novel method for quantifying the short-range order in non-crystalline starch by Raman spectroscopy.

A quantitative method was developed to characterize the short-range order in non-crystalline starch by Raman spectroscopy. The Raman spectra of three forms of non-crystalline starches (just-gelatinized starch, which was heated to the point of having just lost its long-range order but still retaining essentially all of its short-range order, gelatinized starch and amorphous starch) were resolved into subspectra to calculate the short-range ordered phases. By deducting the spectra of amorphous starch using a subtraction technique, the areas of subspectra for short-range ordered phases in just-gelatinized and gelatinized starches were obtained. The ratio of the area for short-range ordered phases in gelatinized starch relative to that in just-gelatinized starch was negatively correlated with water content for gelatinization. Based on this, we propose that this ratio of areas provides a quantitative measure for assessing the short-range order in non-crystalline starch. This study provides an alternative and simpler method to an X-ray diffraction protocol proposed previously.

Revisiting the Formation of Starch-Monoglyceride-Protein Complexes: Effects of Octenyl Succinic Anhydride Modification.

Starch-lipid-protein complexes are attracting increasing attention due to their unique structure and low enzymatic digestibility. However, the mechanisms underlying the formation of these ternary complexes, especially those with monoglycerides as the lipid component, remain unclear. In the present study, potato starch or octenyl succinic anhydride (OSA)-modified potato starch (OSAPS), various monoglycerides (MGs), and beta-lactoglobulin (ßLG) were used in model systems to characterize the formation, structure, and in vitro digestibility of the respective ternary complexes. Colorimetry and live/dead staining assays demonstrated that the OSAPS had good biocompatibility. Experimental data and molecular dynamics simulations showed that both unmodified potato starch and OSAPS formed starch-lipid-protein complexes with MGs and ßLG. Of the two types of starch, OSA formed a greater amount of the more stable type II V-crystallites in complexes, which had greater resistance to in vitro enzymic digestion. This study demonstrated for the first time that starch can interact with MGs and ßLG to form ternary complexes and that OSA esterification of starch promoted the formation of more complexes than unmodified starch.

Inhibition of In Vitro Amylolysis of Wheat Starch by Gluten Peptides.

The effect of gluten peptides (GPs) isolated from a gluten proteolysate on in vitro amylolysis of gelatinized wheat starch was investigated. GPs in a pepsin hydrolysate were fractionated into fractions with molecular weights (MWs) of 500-3000, 3500-7000, 10-17, and 35-48 kDa. The fractions containing peptides with MW > 10 kDa had a strong inhibitory effect on enzyme activity and amylolysis of starch, whereas GPs with MW <10 kDa had no inhibitory effect. Binding constants estimated by surface plasmon resonance showed that peptides in the fractions with MW > 10 kDa bound more strongly to α-amylase, in contrast to peptides of MW <10 kDa. Significant correlations were observed between digestion parameters and equilibrium binding affinity. We conclude that peptides with MW >10 kDa in a pepsin digest of gluten have a strong inhibitory effect on in vitro enzymatic hydrolysis of starch due to their strong binding affinity to α-amylase.

Prior interaction of protein and lipid affects the formation of ternary complexes with starch.

The effects of prior interaction between ß-lactoglobulin (ßLG) and lauric acid (LA) on their formation of ternary complexes with wheat starch (WS) was studied. Firstly, the interaction between ßLG and LA after they were heated at different temperatures between 55 and 95 °C was characterized by fluorescence spectroscopy and molecular dynamics simulation. This showed that a greater degree of ßLG-LA interaction occurred after heating at higher temperatures. The WS-LA-ßLG complexes formed subsequently were analyzed by differential scanning calorimetry, X-ray diffraction, Raman and FTIR spectroscopy, which showed that as interaction of ßLG and LA increased there was an inhibitory action on the formation of ternary complex with WS. Hence, we conclude that there is competition in the ternary systems between the protein and starch to interact with the lipid, and that stronger interaction of the protein and lipid may hinder the formation of ternary complexes with starch.

Neanderthal medics? Evidence for food, cooking, and medicinal plants entrapped in dental calculus.

Neanderthals disappeared sometime between 30,000 and 24,000 years ago. Until recently, Neanderthals were understood to have been predominantly meat-eaters; however, a growing body of evidence suggests their diet also included plants. We present the results of a study, in which sequential thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were combined with morphological analysis of plant microfossils, to identify material entrapped in dental calculus from five Neanderthal individuals from the north Spanish site of El Sidrón. Our results provide the first molecular evidence for inhalation of wood-fire smoke and bitumen or oil shale and ingestion of a range of cooked plant foods. We also offer the first evidence for the use of medicinal plants by a Neanderthal individual. The varied use of plants that we have identified suggests that the Neanderthal occupants of El Sidrón had a sophisticated knowledge of their natural surroundings which included the ability to select and use certain plants.

Effect of Debranching and Differential Ethanol Precipitation on the Formation and Fermentation Properties of Maize Starch-Lipid Complexes.

The objective of this study was to investigate the effect of starch debranching followed by differential ethanol precipitation on the formation and in vitro fermentation of starch-lipid complexes. Three groups of linear glucan chains, with a degree of polymerization (DP) of 383∼2950, 37∼75, and 3∼8, were obtained after debranched maize starch (DMS) was fractionated by differential ethanol precipitation. The glucan fraction with DP 383∼2950 formed only type IIb complexes with lauric acid (LA), whereas the fraction with DP 37∼75 formed predominantly type Ia complexes. The glucan faction with DP 8∼32 did not form V-complexes with LA. In vitro fermentation of the type IIb complexes with human fecal samples promoted the proliferation of butyrate-producing bacteria Megamonas, Blautia, and Megasphaera and resulted in a larger amount of butyrate and total short-chain fatty acids being produced than in similar fermentations of the maize starch-LA complex, DMS-LA complex, and fructo-oligosaccharides. This study showed that starch-lipid complexes with a more stable type IIb crystallite resulted in a greater production of butyrate.