Di Renzo Tiziana, Reale Anna, Boscaino Floriana, Messia Maria C
Institute of Food Science, National Research Council, ISA-CNR, Avellino, Italy.
Department of Agricultural, Environmental and Food Sciences, DiAAA, University of Molise, Campobasso, Italy.
Front Microbiol. 2018 Mar 9;9:429. doi: 10.3389/fmicb.2018.00429. eCollection 2018.
This study identified the odor-active compounds and the qualitative characteristics of doughs from "ancient" grains flours fermented by lactic acid bacteria. For this purpose doughs made with quinoa and Kamut® flours have been produced and inoculated with strains belonging to the species and and compared with fermented doughs made from 100% wheat flour. The quality of the doughs was determined by assessment of pH, total titratable acidity, lactic acid bacteria growth and flavor compounds. The results showed that lactic acid bacteria used were able to grow in the different substrates reaching more than 9.0 log CFU/g after 24 h fermentation, although the best microbial growth was recorded in the doughs made with quinoa flour fermented with I1. Good acidification and heterogeneous aromatic profile were recognized in all the doughs even if the volatile composition mainly derived from microbial specie. Among all the used strains, mostly I1 positively contributed to the aromatic profile of the doughs, independently from flour type, producing the highest amount of different ketones such as, diacetyl, acetoin, 2,6-dimethyl-4-heptanone, 5-methyl-3-hexanone, 4-methyl-3-penten-2-one, volatile compounds highly appreciated in the bakery products for their buttery, fatty and fruity notes. So, the positive characteristic of I1 to enhance the production of desired volatile compounds could make it suitable as adjunct culture starter in the bakery industry. Many differences in volatile organic compounds derived also by the type of flour used. Quinoa fermented doughs were characterized for specific nutty, roasted, acid and buttery tones derived from pyrazines, ketones and acid compounds whereas Kamut® fermented doughs were characterized for fruity, rose, green and sweet tones derived from aldehydes and ketones production. So, the use of quinoa and Kamut® flours opportunely fermented, as partial or complete substitution of wheat flour, may be interesting for producing more balanced bakery products with respect to nutritional aspects and to unique aromatic profile. Furthermore, the supplementation of these flours, rich in protein content and free amino acids, could represent an optimal substrate to enhance the growth of lactic acid bacteria used as starter culture in leavened bakery products.
本研究确定了由乳酸菌发酵的“古老”谷物面粉制成的面团中的气味活性化合物和定性特征。为此，制作了用藜麦粉和卡姆小麦粉制成的面团，并用属于该物种的菌株进行接种，并与由100%小麦粉制成的发酵面团进行比较。通过评估pH值、总可滴定酸度、乳酸菌生长和风味化合物来确定面团的质量。结果表明，所用的乳酸菌能够在不同的底物中生长，发酵24小时后达到超过9.0 log CFU/g，尽管在用藜麦粉与I1发酵制成的面团中记录到最佳的微生物生长。即使挥发性成分主要来自微生物种类，在所有面团中都观察到了良好的酸化和不均匀的香气特征。在所有使用的菌株中，大多是I1对面团的香气特征有积极贡献，与面粉类型无关，产生了最高量的不同酮类，如双乙酰、乙偶姻、2,6-二甲基-4-庚酮、5-甲基-3-己酮、4-甲基-3-戊烯-2-酮，这些挥发性化合物因其黄油味、脂肪味和水果味而在烘焙产品中备受赞赏。因此，I1增强所需挥发性化合物产量的积极特性使其适合作为烘焙行业的辅助发酵剂。挥发性有机化合物的许多差异也源于所用面粉的类型。藜麦发酵面团具有源自吡嗪、酮和酸化合物的特定坚果味、烤香味、酸味和黄油味，而卡姆小麦发酵面团具有源自醛和酮产生的水果味、玫瑰味、绿色味和甜味。因此，适当发酵的藜麦粉和卡姆小麦粉作为小麦粉的部分或完全替代品，在营养方面和独特的香气特征方面，对于生产更均衡的烘焙产品可能是有意义的。此外，这些富含蛋白质和游离氨基酸的面粉的添加，可以代表一种最佳底物，以促进用作发酵烘焙产品发酵剂的乳酸菌的生长。
