Almond Flour Research Articles

Improper Use of a Plant-Based Vitamin C–Deficient Beverage Causes Scurvy in an Infant

Scurvy is a rare disease in developed countries. Risk groups include children with restricted diets, mainly patients who are autistic or have cerebral palsy. Furthermore, consumption of plant-based beverages has increased in recent years, especially in developed countries. When plant-based beverages are the exclusive diet in the first year of life and not consumed as a supplement to formula or breastfeeding, it can result in severe nutritional problems. We report a case of scurvy after exclusive intake of almond beverages and almond flour from 2.5 to 11.0 months of life. The patient was referred for pathologic fractures of the femur, irritability, and failure to thrive. He had typical radiologic signs of scurvy, such as osteopenia, cortical thinning, Wimberger ring, Frankel line, fracture, and periosteal reaction. Moreover, his plasmatic vitamin C level was very low. The child was diagnosed with scurvy and was started on vitamin C replacement therapy at a dose of 300 mg per day. Over the following 3 months, his general condition, the pain in the legs, and the radiologic features improved; the plasmatic vitamin C level was normalized; and the child started walking. In summary, this case demonstrates that scurvy is a new and severe complication of improper use of almond drinks in the first year of life. Manufacturers should indicate that these beverages are inappropriate for infants who consume a vitamin C-deficient diet.

Effects of heat and high-pressure treatments on the solubility and immunoreactivity of almond proteins

The effects of dry and moist heat, autoclave sterilization and high-pressure treatment on the biochemical characteristics and immunological properties of almond proteins were investigated. Changes in the solubility and immunoreactivity of almond proteins extracted from treated almond flour were evaluated using a total protein assay, indirect competitive inhibition enzyme-linked immunosorbent assay (IC-ELISA), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE). Almond proteins were stable during dry-heat treatment at temperatures below 250°C. Dry heat at 400°C, boiling, autoclave sterilization and high-pressure treatment in the presence of water at ⩾500MPa greatly reduced the solubility and immunoreactivity of almond proteins. SDS–PAGE revealed that the protein profiles of almond flour samples treated under these conditions also changed significantly. The synergistic effects of heat, pressure and the presence of water contributed to significant changes in solubility and immunoreactivity of almond proteins.

To investigate the Effect of extrusion process conditions on the functional characteristics of expanded products Based on corn- almond

In recent years, the demand for snacks with optimal functional and nutritional properties has a dramatic increased; hence researching in this regard is considered as an essential task. Almond, is one of the nuts kernel and an important source of nutrients, especially fats, fiber, antioxidants, vitamins and minerals such as iron and calcium. Using this seeds nut in expanded products not only improves the nutritional properties but also it causes to produce a product with optimal functional features. As the screw rate and humidity level have a great effect on the properties of extruded products. In this study, defatted almond flour –corn flour blends (20 - 80) were extruded in a co-rotating twin-screw extruder. Response surface methodology using a central composite design was used to evaluate the effects of independent variables, namely screw rate (120–220 rpm) and humidity level (12–16%) on functional properties (water absorption index, water solubility index and oil absorption index). Based on the process optimization maximum water absorption is 6.54085, water solubility is 25.6472 and oil absorption is 3.09778 that was belong to the production of screw rate 209.17 rpm and the 14% humidity.

Quantitative and qualitative optimization of allergen extraction from peanut and selected tree nuts. Part 1. Screening of optimal extraction conditions using a D-optimal experimental design

A D-optimal design was constructed to optimize allergen extraction efficiency simultaneously from roasted, non-roasted, defatted, and non-defatted almond, hazelnut, peanut, and pistachio flours using three non-denaturing aqueous (phosphate, borate, and carbonate) buffers at various conditions of ionic strength, buffer-to-protein ratio, extraction temperature, and extraction duration. Statistical analysis showed that roasting and non-defatting significantly lowered protein recovery for all nuts. Increasing the temperature and the buffer-to-protein ratio during extraction significantly increased protein recovery, whereas increasing the extraction time had no significant impact. The impact of the three buffers on protein recovery varied significantly among the nuts. Depending on the extraction conditions, protein recovery varied from 19% to 95% for peanut, 31% to 73% for almond, 17% to 64% for pistachio, and 27% to 88% for hazelnut. A modulation by the buffer type and ionic strength of protein and immunoglobuline E binding profiles of extracts was evidenced, where high protein recovery levels did not always correlate with high immunoreactivity.

Nutritional quality and bioactive compounds of partially defatted baru almond flour

This study aimed to investigate the nutritional quality and bioactive potential of partially defatted baru (Dipteryx alataVog.) almond flour (BAF). The flour’s proximate and mineral compositions, total phenolic, tocopherols and carotenoids contents, antioxidant capacity, trypsin inhibitor and amino acid analyses were performed. An experiment was conducted with 24 male Wistar rats in order to evaluate the flour’s protein quality. BAF has high protein, fiber and mineral contents (iron, zinc, magnesium and copper), and it is a source of calcium. BAF presented relevant amounts of total phenolics (625 mg/100g) and good antioxidant capacity (130 µmol/Trolox eq). Autoclaved BAF showed essential amino acids profile, digestibility and protein quality better than in natura BAF. Autoclaved BAF might be used for human consumption as a source of quality protein and bioactive compounds, in healthy diets and processed foods.

Aprovechamiento tecnológico del almendro de india (Terminalia catappa L) para la obtención de productos alimenticios

La almendra del árbol, (Terminalia catappa L.) es un fruto seco que contiene nutrientes como proteína y grasa, similares a otras variedades de almendras de mayor demanda en el mercado, por lo que podría ser empleada en el aprovechamiento industrial y como alternativa nutricional. El objetivo del presente trabajo fue aprovechar tecnológicamente el fruto del almendro, mediante la obtención de harina para la elaboración de tortas y la obtención de almendras confitadas. Para la elaboración de los diferentes productos se realizó la extracción de la semilla del almendro, la cual fue sometida a operaciones unitarias, como tostado y molienda para la obtención de harinas, con la consiguiente elaboración de tortas de acuerdo a las formulaciones tradicionales, sustituyendo el 40% de harina de trigo por harina de almendras. Para la elaboración de almendras confitadas se realizó un tostado y recubrimiento de almendras con jarabes y aditivos alimentarios. Se realizó la comparación de los productos elaborados con controles o con productos comerciales y se sometieron a análisis sensorial. Los resultados organolépticos y sensoriales mostraron que las almendras confitadas y tortas de harina de almendras presentaron buena aceptabilidad por los consumidores de estos productos, constituyéndose así, en una alternativa de uso en la industria, con un importante aporte de nutrientes, sabor y aroma agradable; sin embargo presentaron diferencias significativas con los controles, en la percepción sensorial; de esta manera es posible presentar alternativas positivas como resultados de pruebas con catadores mediante la optimización de las formulaciones empleadas y la estandarización de los procesos.Palabras clave: Harina de almendras; almendras confitadas; almendras de la India; harina de trigo; almendras para pastelería; Almond flour; candied almonds; West Indian almonds; wheat flour; almond pastry

Effect of food matrix and processing on release of almond protein during simulated digestion

The aims of the present work were to assess digestibility of almond protein in the upper gastrointestinal tract, evaluate the effects of food matrix on protein release and assess the persistence of immunoreactive polypeptides generated during simulated digestion. Prunin, the most abundant protein in almond flour, was sensitive to pepsin, with complete digestion after 20 min in the gastric phase. Addition of the surfactant phosphatidylcholine did not affect the rate and kinetic of digestion, as observed by SDS-PAGE analysis and HPLC, in the stomach and the small intestine of either natural or blanched almond flour. However, incorporation of almond flour into a food matrix, such as chocolate mousse and Victorian sponge cake, decreased the rate of almond protein degradation by pepsin and immunoreactivity of almond polypeptides detected by dot blots and sandwich ELISA retained better. Most of the almond protein identified by in-gel tryptic digestion and MALDI-TOF analysis corresponded to prunin, with pI values of 5–7.Further human sera studies are warranted to investigate the relationship between food matrix and almond allergy.

A Murine Monoclonal Antibody Based Enzyme-Linked Immunosorbent Assay for Almond (Prunus dulcis L.) Detection

A sandwich enzyme-linked immunosorbent assay (ELISA) using anti-almond soluble protein rabbit polyclonal antibodies as capture antibodies and murine monoclonal antibody 4C10 as the detection antibodies was developed. The assay is specific and sensitive (3-200 ng almond protein/mL) for almond detection. The standardized assay is accurate (<15% CV) and reproducible (intra- and inter assay variability <15% CV). The assay did not register any cross-reactivity with the tested food matrices, suggesting the assay to be almond amandin specific. The assay could detect the presence of declared almond in the tested matched commercial samples. Further, the assay reliably detected the presence of almonds in the laboratory prepared food samples spiked with almond flour.

Determination of vanillin in commercial food product by adsorptive stripping voltammetry using a boron-doped diamond electrode

A method for the determination of food additive vanillin was developed by adsorptive stripping voltammetry. Its determination was carried out at the anodically pre-treated boron-doped diamond electrode in aqueous solutions. Using square-wave stripping mode, the compound yielded a well-defined voltammetric response in phosphate buffer, pH 2.5 at +1.14V (vs. Ag/AgCl) (a pre-concentration step being carried out at open-circuit condition for 60s). A linear calibration graph was obtained in the concentration range of 0.5–15.0μgmL−1 (3.3×10−6–9.8×10−5molL−1) with a detection limit of 0.024μgmL−1 (1.6×10−7molL−1). As an example, the practical applicability of the proposed method was tested for the determination of this flavouring agent in commercial pudding powder of Keshkule (Turkish milk pudding with almond flour).

Characterization of peeled and unpeeled almond (Prunus amygdalus) flour after electron beam processing

Flours of unpeeled and peeled almond seeds have been irradiated with ionising radiation at 1.5kGy dose by means of 5MeV energy electron beam. The effects of ionising radiation have been studied concerning microbiological parameters, such as total mesophilic counts, mould, yeast, enterobacters, coliform bacteria, as well as physicochemical parameters, free fatty acid, peroxide number, humidity, activity water, aflatoxin, pesticides, and sensory evaluation of attributes regarding only appearance, olfactory and rheological aspects in accordance with the prescription of Italian laws about the consumption of irradiated food. The results, compared with non-irradiated samples from the same supply, show a sharp decrease of pathogen loads while no significant variations of physicochemical parameters and sensory descriptors have been noticed. These results indicate that irradiation at 1.5kGy dose, lower than values usually reported in literature, seems to be still a suitable sanitation treatment to extend the shelf-life of this kind of foodstuff while maintaining its nutritional, safe and sensory characteristics.

Near‐infrared spectroscopy for analysis of oil content and fatty acid profile in almond flour

AbstractAlmond kernels show large variability for oil content and fatty acid profile. The objective of this research was to evaluate the potential of near infrared (NIR) reflectance spectroscopy (NIRS) for the analysis of these traits in almond flour. Ground kernels of 181 accessions collected in 2009 were used for developing calibration equations for oil content and concentrations of individual fatty acids. Calibration equations were developed using second derivative transformation and modified partial least squares regression. They were validated with samples from 179 accessions collected in 2010. The accuracy of calibration equations was measured through the coefficient of determination (r2) in external validation and the ratio of the SD in the validation set to the standard error of prediction (RPD). Both r2 and RPD were high for oil content (r2 = 0.99; RPD = 9.24) and concentrations of oleic (r2 = 0.97; RPD = 5.37) and linoleic acids (r2 = 0.98; RPD = 7.35), revealing that calibration equations for these traits are highly accurate. Conversely, the accuracy of the calibration equations for palmitic (r2 = 0.54; RPD = 1.41) and stearic acids (r2 = 0.52; RPD = 1.44) was too low for allowing their application in practice. NIRS discrimination of oil content and concentrations of oleic and linoleic acids was mainly based on the spectral region from 2240 to 2380 nm.Practical applications: NIRS is a high‐throughput analytical technique that allows fast measurement of several traits in a single analysis without using chemical reagents. We evaluated the feasibility of analyzing oil content and concentrations of palmitic, stearic, oleic, and linoleic acids in almond flour using fruits collected during 2 years from a world germplasm collection. The fruits collected in 2009 were used for NIRS calibration, whereas the fruits collected in 2010 were used for validation. NIRS equations were highly accurate for measuring oil content and concentrations of oleic and linoleic acids, which are important traits defining the quality of almond flour for specific uses in the food industry. These results have applications both in the research laboratory and the food industry, where NIRS is becoming a widely used technique for quality control.

Food matrix and processing affect almond protein release during simulated digestion

Understanding the fate of proteins during digestion is of especial relevance to understanding the basis of food allergies. Little is known of the immunological mechanisms involved in the sensitisation of an individual towards a food and, with the exception of the fruit and vegetable allergies (which appear to be secondary responses to tree and weed pollen allergies), it is thought that food allergens (or fragments thereof) must cross the gastrointestinal (GI) mucosa in order to interact with the immune system. This is also a prerequisite for an allergen to elicit a reaction in an individual who has already become sensitised. When food is ingested it is crushed and sheared in the mouth where it is mixed with saliva, subjected to gastric processing for a variable period where the pH may fall to as low as 2 and on entering the small intestine it is neutralised and subjected to the duodenal, jejunal and ileal environments on its passage to the large intestine. During all these phases it is mixed with enzymes (amylases, proteases, lipases) and in the duodenum to detergents (bile salts). Here we describe the release of almond protein during simulated GI digestion and the effects of food matrix and processing on its release. A Dynamic Gastric Model (DGM) was used to represent the in vivo physiological conditions of the gastric environment with addition of acid secretions, gastric enzymes and surfactants. Results obtained by SDS-PAGE analysis and HPLC showed a slower kinetic of protein digestion when almond flour was incorporated within a chocolate dessert and a Victorian sponge. In-gel tryptic digestion coupled with MALDI-ToF/ToF mass spectrometer was used to follow the rate of almond protein digestion in the food matrix. Food matrix and processing affect digestibility of almond protein in the upper GI tract. This work has been funded by the Almond Board of California.

Acute and second-meal effects of almond form in impaired glucose tolerant adults: a randomized crossover trial

BackgroundNut consumption may reduce the risk of developing type 2 diabetes. The aim of the current study was to measure the acute and second-meal effects of morning almond consumption and determine the contribution of different nut fractions.MethodsFourteen impaired glucose tolerant (IGT) adults participated in a randomized, 5-arm, crossover design study where whole almonds (WA), almond butter (AB), defatted almond flour (AF), almond oil (AO) or no almonds (vehicle - V) were incorporated into a 75 g available carbohydrate-matched breakfast meal. Postprandial concentrations of blood glucose, insulin, non-esterified free fatty acids (NEFA), glucagon-like peptide-1 (GLP-1) and appetitive sensations were assessed after treatment breakfasts and a standard lunch.ResultsWA significantly attenuated second-meal and daylong blood glucose incremental area under the curve (AUCI) and provided the greatest daylong feeling of fullness. AB and AO decreased blood glucose AUCI in the morning period and daylong blood glucose AUCI was attenuated with AO. WA and AO elicited a greater second-meal insulin response, particularly in the early postprandial phase, and concurrently suppressed the second-meal NEFA response. GLP-1 concentrations did not vary significantly between treatments.ConclusionsInclusion of almonds in the breakfast meal decreased blood glucose concentrations and increased satiety both acutely and after a second-meal in adults with IGT. The lipid component of almonds is likely responsible for the immediate post-ingestive response, although it cannot explain the differential second-meal response to AB versus WA and AO.

Influence of food matrix and processing on release of almond protein during simulated digestion

Understanding how food matrix and processing affect protein digestion is key to determining stability of certain protein which may be involved in allergenic reactions. Here we describe the release of protein from almond during gastrointestinal (GI) digestion and the effects of food structure on the stability of the globulins and the albumins. A dynamic gastric model of digestion (DGM) which provides a realistic and predictive simulation of the physical and chemical processing and accurately mimics both the transit time and the luminal environment within the human stomach was used for the digestion studies. Results showed a rapid protein digestion under the low pH conditions of the stomach, with no differences between blanched almond flour and almond flour with skin. A slower kinetic of protein digestion was observed when almond flour was incorporated within a food matrix, such as chocolate dessert. Food matrix influences almond protein digestibility in relation to different residence time in the gut and effects of food processing.This work has been funded by the Almond Board of California.

Manipulation of lipid bioaccessibility of almond seeds influences postprandial lipemia in healthy human subjects

Background: Plant cell walls are known to influence the rate and extent of lipid release from plant food tissues during digestion; however, the effect of cell wall structure on postprandial lipemia is unknown.Objective: The objective was to investigate the effects of lipid release (bioaccessibility) on postprandial lipemia by comparing lipid encapsulated by cell walls with lipid present as free oil.Design: A randomized crossover trial (n = 20 men) compared the effects of 3 meals containing 54 g fat provided as whole almond seed macroparticles (WA), almond oil and defatted almond flour (AO), or a sunflower oil blend as control (CO) on postprandial changes in oxidative stress (8-isoprostane F2α concentrations), vascular tone (peripheral augmentation index), and plasma triacylglycerol, glucose, and insulin concentrations.Results: The postprandial increase in plasma triacylglycerol was lower [74% and 58% lower incremental area under curve (iAUC)] after the WA meal than after the AO and CO meals (P < 0.001). Increases in plasma glucose concentrations (0–180 min) were significantly higher after the WA meal (iAUC: 114; 95% CI: 76, 153) than after the AO meal (iAUC: 74; 95% CI: 48, 99) (P < 0.05), but no significant differences from the CO meal were observed (iAUC: 88; 95% CI: 66, 109). The peak reductions in peripheral augmentation index after the WA, AO, and CO meals (−9.5%, −10.1%, and −12.6%, respectively, at 2 h) were not significantly different between meals. Plasma 8-isoprostane F2α and insulin concentrations did not differ significantly between meals.Conclusions: The bioaccessibility of lipid in almond seeds, which is regulated by the structure and properties of cell walls, plays a primary role in determining postprandial lipemia.

Purification, Crystallization and Preliminary X-ray Characterization of Prunin-1, a Major Component of the Almond (Prunus dulcis) Allergen Amandin

The 11S globulins from plant seeds account for a number of major food allergens. Because of the interest in the structural basis underlying the allergenicity of food allergens, we sought to crystallize the main 11S seed storage protein from almond ( Prunus dulcis). Prunin-1 (Pru1) was purified from defatted almond flour by water extraction, cryoprecipitation, followed by sequential anion exchange, hydrophobic interaction, and size exclusion chromatography. Single crystals of Pru1 were obtained in a screening with a crystal screen kit, using the hanging-drop vapor diffusion method. Diffraction quality crystals were grown after optimization. The Pru1 crystals diffracted to at least 3.0 A and belong to the tetragonal space group P4(1)22, with unit cell parameters of a = b = 150.912 A, c = 165.248 A. Self-rotation functions and molecular replacement calculations showed that there are three molecules in the asymmetry unit with water content of 51.41%. The three Pru1 protomers are related by a noncrystallographic 3-fold axis and they form a doughnut-shaped trimer. Two prunin trimers form a homohexamer. Elucidation of prunin structure will allow further characterization of the allergenic features of the 11S protein allergens at the molecular level.

Manipulation of lipid bioaccessibility of almonds influences postprandial lipemia in healthy human subjects

An exaggerated postprandial lipemic response is associated with increased risk of coronary heart disease, due to acute effects on lipids, oxidative stress, hemostatic factors and vascular function. Lipid released slowly from a complex food matrix during digestion may attenuate postprandial lipemia1. The present study therefore investigates the effects of lipid release (lipid bioaccessibility (LB)) on postprandial changes (over 8h) in plasma triacylglycerol (TAG) concentration, oxidative stress (measured by 8‐isoprostane F2α) and vascular function (measured by peripheral augmentation index (PAIx)). Subjects (n = 20, aged 18–40y) were fed test meals containing 50g fat of low LB (intact whole almonds; WA), high LB (almond oil + defatted almond flour; AO) or as a control meal (CO) in a randomised cross‐over design, with 1‐wk washout. The postprandial increase in plasma TAG was significantly lower (74% &amp; 58% lower incremental area under curve) following the WA vs. the AO and CO meals, respectively (P&lt;0.001). The peak reduction in PAIx (by −9.5%, −10.1% &amp; −12.6% at 2h following WA, AO and CO meals respectively, time effect; P&lt;0.001) was not significantly different between meals. There were no changes in plasma 8‐isoprostane F2α concentrations. Reducing LB of almonds beneficially influences postprandial lipemia.This study was funded by the Almond Board of California

Study on formation of starch–lipid complexes during extrusion-cooking of almond flour

A blend containing almond and wheat flours (about 1:2.5, dry basis) was extruded through a co-rotating twin-screw extruder with a screw diameter of 25 mm. The effects of barrel temperature (61.72–118.28 °C) and feed moisture (21.17–26.83%) on starch–lipid complex formation (X-ray diffraction, melting enthalpy, and complexing index) as well as on fat loss (which occurs during extrusion processing), break strength, deformability and expansion index of extrudates were investigated using response surface methodology (RSM). The only variable that had a significant influence on the formation of starch–lipid complexes was feed moisture (the high values of melting enthalpy and complexing index, i.e. 3.67 J/g and 94.34%, respectively, were obtained with the smallest value of feed moisture, i.e. 21.17%). The highest fat loss and the hardest texture of extrudates were obtained at the highest values of barrel temperature and feed moisture (118.28 °C and 26.83%, respectively).

Sensory and instrumental assessment of Chinese moon cake: Influences of almond flour, maltitol syrup, fat, and gums

Abstract The objectives of this research were to investigate sensory and instrumental (texture and color) quality attributes and their relation of newly formulated Chinese moon cakes: California almond flour and maltitol syrup were used as the replacement of wheat flour and sucrose syrup, respectively and gum was added as the fat-replacer. Sensory analysis showed that addition of almond flour had the most significant ( P ⩽ 0.05) effects on the properties of moon cakes, and the 70% replaced moon cake was most favored by the sensory panel: almond flavor, color, shininess, stickiness, oiliness, and chewiness increased and hardness decreased. Sweetness and moon cake color decreased significantly as maltitol syrup replaced sucrose syrup. The reduction of fat decreased shininess, stickiness, and oiliness but the addition of gums alleviated the impaired attributes. The instrumental data were highly correlated with those from the sensory analysis for hardness, chewiness, and stickiness ( R 2 = 0.97, 0.96, and 0.71, respectively).

Cloning and characterization of profilin (Pru du 4), a cross-reactive almond ( Prunus dulcis) allergen

The identity of allergenic almond proteins is incomplete. Our objective was to characterize patient IgE reactivity to a recombinant and corresponding native almond allergen. An almond cDNA library was screened with sera from patients with allergy for IgE binding proteins. Two reactive clones were sequenced, and 1 was expressed. The expressed recombinant allergen and its native counterpart (purified from unprocessed almond flour) were assayed by 1-dimensional and 2-dimensional gel electrophoresis, dot blot, and ELISA, and screened for cross-reactivity with grass profilin. The 2 selected clones encoded profilin (designated Pru du 4) sequences that differed by 2 silent mutations. By dot-blot analyses, 6 of 18 patient sera (33%) reacted with the recombinant Pru du 4 protein, and 8 of 18 (44%) reacted with the native form. ELISA results were similar. Almond and ryegrass profilins were mutually inhibitable. Two-dimensional immunoblotting revealed the presence of more than 1 native almond profilin isoform. The strength of reactivity of some patients' serum IgE differed markedly between assays and between native and recombinant profilins. Almond nut profilin is an IgE-binding food protein that is cross-reactive with grass pollen profilin and is susceptible to denaturation, resulting in variable reactivity between assay types and between patients. Serum IgE of nearly half of the tested patients with almond allergy reacts with almond nut profilin. Because most patients also had pollinosis, the well-known cross-reactivity between pollen and food profilins could account for this pattern of reactivity.