Alyssa Hidalgo

Kinetics of carotenoids degradation during the storage of einkorn (Triticum monococcum L. ssp. monococcum) and bread wheat (Triticum aestivum L. ssp. aestivum) flours.

To evaluate the effect of storage temperature, the degradation kinetics of carotenoids in wholemeal and white flour of einkorn cv. Monlis and bread wheat cv. Serio, stored at -20, 5, 20, 30, and 38 degrees C, was assessed by normal-phase high-performance liquid chromatography. In Monlis, the carotenoids content (8.1 and 9.8 mg/kg for wholemeal and white flour, respectively) was 8-fold higher than in Serio (1.0 and 1.1 mg/kg). Only lutein and zeaxanthin were detected in bread wheat, while significant quantities of (alpha and beta)-carotene and beta-cryptoxanthin were observed in einkorn. Carotenoids degradation was influenced by temperature and time, following first-order kinetics. The degradation rate was similar in wholemeal and white flour; however, loss of lutein and total carotenoids was faster in Serio than in Monlis. The activation energy E(a) ranged from 35.2 to 52.5 kJ/mol. Temperatures not exceeding 20 degrees C better preserve carotenoids content and are recommended for long-term storage.

Wheat germ : not only a by-product

The wheat germ (embryonic axis and scutellum) represents about 2.5–3.8% of total seed weight and is an important by-product of the flour milling industry. The germ contains about 10–15% lipids, 26–35% proteins, 17% sugars, 1.5–4.5% fibre and 4% minerals, as well as significant quantities of bioactive compounds such as tocopherols [300–740 mg/kg dry matter (DM)], phytosterols (24–50 mg/kg), policosanols (10 mg/kg), carotenoids (4–38 mg/kg), thiamin (15–23 mg/kg) and riboflavin (6–10 mg/kg). Oil recovery is achieved by mechanical pressing or solvent extraction, which retrieve about 50% or 90% lipids, respectively; innovative approaches, such as supercritical carbon dioxide extraction, are also proposed. The oil is rich in triglycerides (57% of total lipids), mainly linoleic (18:2), palmitic (16:0) and oleic (18:1) acids, but relevant amounts of sterols, mono- and diglycerides, phospho- and glycolipids are present. The lypophilic antioxidants tocopherols and carotenoids are also abundant. The main by-product of oil extraction is defatted germ meal, which has high protein content (30–32%), is rich in albumin (34.5% of total protein) and globulin (15.6%), and thus presents a well-balanced amino acid profile. Its principal mineral constituents are potassium, magnesium, calcium, zinc and manganese, in decreasing order. Total flavonoid content is about 0.35 g rutin equivalent/100 g DM. The wheat germ is therefore a unique source of concentrated nutrients, highly valued as food supplement. While the oil is widely appreciated for its pharmaceutical and nutritional value, the defatted germ meal is a promising source of high-quality vegetable proteins. Better nutrient separation from the kernel and improved fractioning techniques could also provide high-purity molecules with positive health benefits.

Influence of Genetic and Environmental Factors on Selected Nutritional Traits of Triticum monococcum

To evaluate the effect of genotype, year, and location on protein, lipid, tocol, and lutein content and on fatty acids composition of wholemeal flour, five einkorns (Triticum monococcum L. ssp. monococcum) and one control bread wheat were cropped in Italy for two years in four different locations. Genotype and year exerted major effects on protein, tocotrienol, and lutein contents, while tocopherol and lipid contents were influenced only by the genotype. The concentrations of linoleic, oleic, and palmitic acids (the most abundant among the 14 fatty acids identified), as well as of saturated (SFA), monosaturated (MUFA), and polyunsaturated (PUFA) fatty acids, differed between einkorns and control and, to some extent, years were constant across locations. Notwithstanding the environmental variation, all einkorns consistently showed higher protein (on average, +59%), lipid (+50%), tocotrienol (+88%), total tocol (+46%), lutein (+483%), and MUFA (+53%) content, along with lower SFA (-21%) and PUFA (-8%) than the bread wheat control.

Nutritional properties of einkorn wheat (Triticum monococcum L.)

The hulled wheat einkorn (Triticum monococcum L. ssp. monococcum), a staple food of early farmers for many thousand years, today is cropped only in small areas of the Mediterranean region and continental Europe. Increasing attention to the nutritional quality of foods has fostered renewed interest in this low-impact crop. The reappraisal of einkorn quality evidenced that this ancient wheat has some dietary advantages over polyploid wheats. Einkorn wholemeal is poor in dietary fibre but rich in proteins, lipids (mostly unsaturated fatty acids), fructans and trace elements (including zinc and iron). The good concentration of several antioxidant compounds (carotenoids, tocols, conjugated polyphenols, alkylresorcinols and phytosterols) and low β-amylase and lipoxygenase activities (which limit antioxidant degradation during food processing) contribute to the excellent nutritional properties of its flour, superior to those of other wheats. Conversely, einkorn has relatively low bound polyphenol content and high polyphenol oxidase activity. In spite of eliciting weaker toxic reactions than other Triticum species, einkorn is not suitable for coeliacs. Current trends towards the consumption of functional foods suggest that this cereal may still play a significant role in human consumption, especially in the development of new or special foods with superior nutritional quality.

Wheat flour granulometry determines colour perception

Einkorn, durum wheat and Kamut® are rich of carotenoids, antioxidants with beneficial effects on human health. In the present study the effect of flour granule size on carotenoid content and colour was assessed; furthermore, the suitability of two colorimeters (Minolta Chroma meter CR-210 and Minolta Chroma meter II Reflectance), a spectrophotometer (Jasco V-650 with integrating sphere) and image analysis to define colour and determine carotenoid concentration in wheat flours of different granulometry was tested. Carotenoid content did not vary across flours of diverse size, except in the finest einkorn fraction (<80μm), which had lower concentration. For all instruments colour coordinate L* decreased and b* increased with flour size growth, while a* varied with the different devices. A Principal Components Analysis (PCA), performed considering carotenoid content and all colorimetric indices, distinguished einkorn from durum and Kamut®, and divided samples of different granulometry; a similar result was achieved by a PCA performed on the absorbance spectra from the integrating sphere. The PCA on image texture data classified the samples following flour size. In conclusion, flour colour is determined not only by carotenoid content but also by flour particle size: therefore, direct colour measurement seems not suitable to predict flour carotenoid content.

Heat damage of water biscuits from einkorn, durum and bread wheat flours.

To limit heat damage and improve the nutritional properties of bakery products, furosine, glucosylisomaltol, hydroxymethylfurfural, furfural, sugars, α-amylase, β-amylase and colour were assessed during the production of water biscuits from three einkorn, three bread and one durum wheat flours. Heat damage indices, colour and aw development during baking (from 25 to 75min duration) of water biscuits from one bread wheat were also studied. Furosine was more abundant in durum (86.0±6.29mg/100g protein) and bread wheat (42.5±6.93) than in einkorn (15.7±3.92) water biscuits, while GLI was detected only in durum (10.0±2.02mg/kgDM) and bread wheat (5.2±1.52) products; hydroxymethylfurfural and furfural were always absent. The limited heat damage of Triticum monococcum products was probably due to the moderate β-amylase activity of einkorn, and hence to the low maltose content of its mixes. The colour was correlated to heat damage, as einkorn water biscuits were lighter than those from other wheats.

Heat damage and in vitro starch digestibility of puffed wheat kernels

The effect of processing conditions on heat damage, starch digestibility, release of advanced glycation end products (AGEs) and antioxidant capacity of puffed cereals was studied. The determination of several markers arising from Maillard reaction proved pyrraline (PYR) and hydroxymethylfurfural (HMF) as the most reliable indices of heat load applied during puffing. The considerable heat load was evidenced by the high levels of both PYR (57.6-153.4 mg kg(-1) dry matter) and HMF (13-51.2 mg kg(-1) dry matter). For cost and simplicity, HMF looked like the most appropriate index in puffed cereals. Puffing influenced starch in vitro digestibility, being most of the starch (81-93%) hydrolyzed to maltotriose, maltose and glucose whereas only limited amounts of AGEs were released. The relevant antioxidant capacity revealed by digested puffed kernels can be ascribed to both the new formed Maillard reaction products and the conditions adopted during in vitro digestion.

Bioactive compounds and antioxidant properties of pseudocereals-enriched water biscuits and their in vitro digestates

Carotenoids, tocols, phenolic acids and antioxidant capacity were studied during in vitro digestion of water biscuits (WB) from bread wheat, einkorn and einkorn-pseudocereals. Antioxidant and cytotoxic activities of digestates were also measured using a 70% Caco2/30% HT-29 human intestinal co-culture layer. Antioxidant profiles differed among WB formulations. Only hydrophilic molecules were solubilised by gastric digestion. After intestinal digestion, 77% carotenoids and 67% tocols were released. Soluble-conjugated phenolic acids increased (30%) and insoluble-bound forms decreased (17%), suggesting partial conversion from bound to conjugated form. After intestinal digestion, antioxidant capacity increased regardless of type and amount of antioxidants in undigested or digested WB. All WB, especially those with quinoa flour, reduced the AAPH pro-oxidant capacity in co-culture cells. These results highlight the potential health benefits of underutilized crops and the need for in vitro or in vivo models to better address potential bioactivity at intestinal and target organs level.

Influence of water biscuit processing and kernel puffing on the phenolic acid content and the antioxidant activity of einkorn and bread wheat

The whole meal flour of wheat is rich in phenolic acids, which provide a relevant antioxidant activity to food products. Aim of this research was to assess the influence of processing on phenolic acid content and antioxidant activity of whole meal flour water biscuits and puffed kernels of einkorn and bread wheat. To this end, the evolution of syringaldehyde, ferulic, vanillic, syringic, p-coumaric, p-hydroxybenzoic, and caffeic acids was studied during manufacturing. Overall, from flour to water biscuit, the total soluble conjugated phenolic acids increased slightly in einkorn, while the insoluble bound phenolic acids decreased in all the accessions as a consequence of losses during the mixing step. In the puffed kernels, instead, the total soluble conjugated phenolic acids increased markedly, while the bound phenolics did not show any clear change, evidencing their high thermal stability. The antioxidant activity, measured by FRAP and ABTS, increased during processing and was highest under the most drastic puffing conditions.

Crossability of Triticum urartu and Triticum monococcum Wheats, Homoeologous Recombination, and Description of a Panel of Interspecific Introgression Lines

Triticum monococcum (genome Am) and T. urartu (genome Au) are diploid wheats, with the first having been domesticated in the Neolithic Era and the second being a wild species. In a germplasm collection, rare wild T. urartu lines with the presence of T. monococcum alleles were found. This stimulated our interest to develop interspecific introgression lines of T. urartu in T. monococcum, a breeding tool currently implemented in several crop species. Moreover, the experiments reported were designed to reveal the existence in nature of Am/Au intermediate forms and to clarify whether the two species are at least marginally sexually compatible. From hand-made interspecific crosses, almost-sterile F1 plants were obtained when the seed-bearing parent was T. monococcum. A high degree of fertility was, however, evident in some advanced generations, particularly when T. urartu donors were molecularly more related to T. monococcum. Analysis of the marker populations demonstrated chromosome pairing and recombination in F1 hybrid plants. Forty-six introgression lines were developed using a line of T. monococcum with several positive agronomic traits as a recurrent parent. Microsatellite markers were tested on Au and Am genomes, ordered in a T. monococcum molecular map, and used to characterize the exotic DNA fragments present in each introgression line. In a test based on 28 interspecific introgression lines, the existence of genetic variation associated with T. urartu chromosome fragments was proven for the seed content of carotenoids, lutein, β-cryptoxanthin, and zinc. The molecular state of available introgression lines is summarized.